There’s a particular kind of cake that stops conversation the moment it arrives at the table. This is that cake. Ivory-pale and deceptively simple on the outside, each slice reveals a dense, velvety crumb shot through with swirls of deep-ruby raspberry jam, the sweet perfume of white chocolate rising to meet the bright, almost winey tartness of the fruit. It’s a cake that feels elegant without being fussy, celebratory without requiring a special occasion.
What sets this mud cake apart from a standard white chocolate layer cake is the technique borrowed from classic Australian-style mud cakes: the butter, white chocolate, and sugar are gently melted together before the flour and eggs are added. This produces a batter that is almost impossibly silky and yields a crumb that is dense, moist, and deeply flavoured rather than light and airy. The raspberry jam is not stirred in but swirled through at the very last moment, keeping distinct ribbons of fruit flavour that contrast beautifully with every bite. The whipped ganache frosting, made by chilling and then whipping melted white chocolate and cream, sets to a texture somewhere between buttercream and mousse, luxurious without being cloyingly sweet.
This is a medium-difficulty bake, and while it does require a little patience (the melted chocolate base needs time to cool, and the ganache needs a good chill before whipping), none of the steps are technically demanding. It’s an ideal project for a confident weekend baker, and it is absolutely stunning as a birthday cake, dinner party centrepiece, or Valentine’s Day showstopper.
✓ Vegetarian
Servings:
12
servings
12
servings
Ingredients
- Decorating
- 250 ggood-quality white chocolate, roughly chopped (about 1.5 cups)
- 250 gunsalted butter, cubed (about 1 cup plus 2 tbsp)
- 300 gcaster sugar or superfine sugar (about 1.5 cups)
- 250 mlwhole milk (about 1 cup)
- 2 tsppure vanilla extract
- 300 gall-purpose flour (about 2.5 cups, spooned and leveled)
- 1 tspbaking powder
- 0.5 tspbaking soda
- 0.5 tspfine sea salt
- 3 largeeggs, at room temperature
- 80 mlsour cream (about 1/3 cup), at room temperature
- 200 gseedless raspberry jam (about 0.5 cup plus 3 tbsp)
- —For the Whipped White Chocolate Ganache Frosting:
- 500 ggood-quality white chocolate, finely chopped (about 3 cups)
- 480 mlheavy whipping cream, divided (2 cups total: 160 ml hot, 320 ml cold)
- 1 tsppure vanilla extract
- —Pinch of fine sea salt
- —To Finish:
- 120 gfresh raspberries (about 1 cup)
- Dusting
- 30 gfreeze-dried raspberry powder or crushed freeze-dried raspberries (about 3 tbsp), optional
Ingredient Substitutions
caster sugar
sour cream
whole milk
white chocolate (cake)
seedless raspberry jam
eggs
Instructions
🔧 Equipment
two 9-inch round cake pans
parchment paper
medium saucepan
large mixing bowl
heatproof spatula
balloon whisk
stand mixer or hand mixer with whisk attachment
wire cooling rack
offset spatula
fine-mesh sieve
kitchen scale
toothpick or cake tester
plastic wrap
skewer or butter knife (for swirling)
6-quart slow cooker (for slow cooker method)
350ml or larger microwave-safe mug (for microwave method)
oven thermometer (recommended)
- Make the ganache frosting first so it has time to chill. Place the finely chopped white chocolate in a heatproof bowl. Heat 160ml (about 2/3 cup) of the heavy cream in a small saucepan over medium heat until it just begins to simmer around the edges. Do not boil. Pour the hot cream over the chocolate and let it sit undisturbed for 2 minutes. Add the vanilla extract and a pinch of salt, then stir gently from the centre outward until completely smooth. If any chocolate remains unmelted, microwave in 10-second bursts, stirring between each. Pour in the remaining 320ml (about 1.25 cups) of cold cream and stir to combine. Cover the surface directly with plastic wrap and refrigerate for a minimum of 4 hours, or overnight. (This can be made the night before.)
- When ready to bake, preheat your oven to 325°F (160°C) with a rack in the centre position. Grease two 9-inch round cake pans generously with butter, line the bottoms with parchment paper circles, then grease the parchment too. Dust lightly with flour, tapping out any excess.
- In a medium saucepan over low heat, combine the chopped white chocolate, cubed butter, caster sugar, and whole milk. Stir constantly with a heatproof spatula until the butter and chocolate have completely melted and the mixture is smooth and glossy. Do not let it simmer. Remove from the heat, pour into a large mixing bowl, and stir in the vanilla extract. Allow to cool until it reaches room temperature, about 25 to 30 minutes. It should feel just barely warm to the touch, not hot. (A hot mixture will scramble your eggs.)
- Once the chocolate mixture has cooled, whisk in the eggs one at a time, whisking well after each addition until fully incorporated. Whisk in the sour cream until smooth.
- Sift the flour, baking powder, baking soda, and salt directly into the bowl. Using a large whisk or rubber spatula, fold gently until no dry streaks remain. The batter will be fairly fluid, somewhere between a poured batter and a regular cake batter. This is correct.
- Divide the batter evenly between the two prepared pans (a kitchen scale is helpful here for even layers). Warm the raspberry jam briefly in the microwave for 15 to 20 seconds until it is just pourable but not hot. Drop spoonfuls of jam across the surface of each pan of batter, using half the jam per pan. Use a skewer, toothpick, or butter knife to swirl the jam gently through the top layer of batter in loose figure-eight motions. Do not over-swirl or the jam will disappear into the batter.
- Bake for 55 to 65 minutes, until the tops are golden and set, the edges have pulled away slightly from the sides of the pans, and a toothpick inserted into the centre comes out with a few moist crumbs but no wet batter. Mud cakes are dense and can look quite dark and cracked on top, which is completely normal. Allow the cakes to cool in their pans on a wire rack for 20 minutes before turning out. Cool completely on the rack before frosting, at least 1.5 to 2 hours.
- Remove the chilled ganache from the refrigerator. Transfer it to the bowl of a stand mixer fitted with the whisk attachment, or use a hand mixer with a large bowl. Whip on medium-high speed for 2 to 4 minutes until the ganache transforms from a pale liquid into a thick, fluffy, spreadable frosting that holds soft peaks. Watch carefully as it can go from perfect to over-whipped quickly. It should look like a very thick whipped cream. Use immediately.
- Place one cooled cake layer on a cake board or serving plate, flat side up. Spread roughly one-third of the whipped ganache over the top in an even layer. Place the second cake layer on top, pressing gently. Use the remaining frosting to cover the top and sides of the cake with an offset spatula, creating swirls or a smooth finish as you prefer. Decorate with fresh raspberries and a dusting of freeze-dried raspberry powder if using. Refrigerate for at least 30 minutes before slicing to allow the frosting to set.
This method produces a single, thicker mud cake with an incredibly dense and fudgy centre. It is particularly good for those who want a pudding-like texture, or when the oven is occupied. You will need a 6-quart or larger oval or round slow cooker. The cake will not brown on top but will be fully set and sliceable once cooled.
- Prepare the ganache frosting following Step 1 of the Oven method above. Refrigerate for at least 4 hours.
- Line the insert of a 6-quart slow cooker with two layers of paper towels laid across the top of the insert (not inside it). These will absorb condensation during cooking and prevent a soggy top on the cake. Cut a piece of parchment paper to fit the bottom of the insert and press it in place. Grease the parchment and the sides of the insert generously with butter or cooking spray.
- Prepare the full cake batter following Steps 3, 4, and 5 of the Oven method, melting the white chocolate, butter, sugar, and milk together in a saucepan, cooling it completely, then whisking in the eggs and sour cream, and folding in the dry ingredients.
- Pour the entire batter into the prepared slow cooker insert. Warm the raspberry jam until pourable and drop spoonfuls across the top. Swirl gently with a skewer. Place the paper towels across the top of the insert (they should rest on the rim, not touching the batter), then place the lid on top, trapping the paper towels between the lid and the rim to absorb steam.
- Cook on High for 2.5 to 3 hours. Begin checking at the 2.5-hour mark. The cake is done when the edges are fully set and slightly pulling away from the sides, the top feels set and no longer jiggly when the insert is gently moved, and a toothpick inserted near the centre comes out with moist but not wet crumbs. The very centre may seem slightly underdone but will firm up as it cools. Turn off the slow cooker and remove the lid. Allow the cake to cool in the insert for 30 minutes, then carefully lift it out using the parchment paper and cool completely on a wire rack.
- Whip the chilled ganache following Step 8 of the Oven method. Frost the top and sides of the cooled single-layer cake and decorate with fresh raspberries. Because this cake is a single, taller layer rather than two thinner ones, slice it into wedges as you would a standard single-layer cake.
This is a scaled-down, single-serving version that captures the spirit of the white chocolate raspberry mud cake in just minutes. The texture is softer and more pudding-like than the baked version, but deeply satisfying for a weeknight treat. Serve directly in the mug with a spoonful of raspberry jam and a dollop of lightly whipped cream or a drizzle of white chocolate.
- In a microwave-safe mug (at least 350ml or 12 oz capacity to prevent overflow), combine 25g (about 1 tbsp plus 2 tsp) finely chopped white chocolate and 25g (about 1.5 tbsp) unsalted butter. Microwave in 20-second bursts, stirring between each, until melted and smooth. Let cool for 2 minutes.
- Whisk 2 tablespoons of caster sugar and 1 small egg into the melted chocolate mixture until smooth. Stir in 1 tablespoon of whole milk, 1 tablespoon of sour cream, and 0.25 teaspoon of vanilla extract.
- Add 3 tablespoons (about 25g) of all-purpose flour, a small pinch of baking powder (about 0.125 tsp), and a tiny pinch of fine sea salt. Stir until just combined and no dry flour remains. Do not over-mix.
- Drop 1 heaped teaspoon of seedless raspberry jam onto the top of the batter. Use a toothpick to gently swirl it in once or twice.
- Microwave on full power (1000W) for 90 seconds. The top should look just set but still slightly moist in the very centre. If the centre still looks completely liquid, microwave for an additional 10 to 20 seconds. Remember that the mug cake will continue to cook from residual heat for about 1 minute after stopping. Allow to rest for 1 minute before eating. Top with a spoonful of lightly whipped cream and a few fresh raspberries to serve.
Nutrition Per Serving
Per 1 serving (makes one 9-inch two-layer cake)
685Calories
74gCarbs
58gSugar
40gFat
8gProtein
Why This Recipe Works
The defining technique of a mud cake is melting the fat, sugar, and chocolate together before adding the dry ingredients, and this is what produces that signature dense, fudgy crumb. In a conventional creamed cake, you beat butter and sugar together to incorporate air, which then expands during baking to create lift. A mud cake does the opposite: by dissolving the sugar into warm butter and chocolate, you create a base with very little trapped air. The result is a tight, rich crumb with a brownie-like density that stays moist for days. The sour cream adds a small amount of acidity, which reacts with the baking soda to provide just enough lift to keep the cake from being completely flat, while its fat content adds to the moistness.
The raspberry jam swirl works best when the jam is warmed briefly so it is fluid enough to move through the batter without sinking entirely to the bottom or being fully absorbed. Swirling rather than folding is key: you want visible streaks of jam, not a pink batter. The tartness of raspberry is one of the few fruit flavours bold enough to cut through the richness of white chocolate without being overwhelmed. The acidity also provides a palate-cleansing contrast that makes each bite feel less heavy than it actually is.
The whipped ganache frosting relies on the same science as whipped cream: fat globules in cream, when cold, can trap air when agitated. By melting white chocolate into cream and chilling the mixture thoroughly, you create a fat-rich liquid that, once cold enough, will whip into a stable, aerated foam. The key is patience: if the ganache is even slightly too warm when you whip it, it will remain liquid and loose. If you find your ganache is not whipping up properly, simply return it to the refrigerator for another 30 to 60 minutes and try again. Using white chocolate with real cocoa butter (rather than compound chocolate) is essential here, as cocoa butter sets firm when cold and is what gives the frosting its structure.
Baker’s Tips
- Use the best white chocolate you can reasonably find. White chocolate is the dominant flavour in this cake, and the difference between a 28% cocoa butter couverture and a cheap baking chip is enormous. Lindt, Ghirardelli, or Callebaut are widely available and reliable.
- Do not rush the cooling of the melted chocolate base. If it is too warm when you add the eggs, the eggs will partially cook and you will get a lumpy batter. It should feel just barely warm or at room temperature before you proceed.
- Weigh your batter when dividing it between the two pans for even layers. Uneven layers mean uneven baking times.
- For very clean, distinct jam swirls, do not swirl more than 3 or 4 passes with your skewer per pan. Over-swirling fully incorporates the jam and you lose the visual effect and the flavour pockets.
- Mud cakes often look alarmingly dark and cracked on top when they come out of the oven. This is completely normal for this style of cake. The crust will soften as the cake cools and once frosted you will never see it.
- If your whipped ganache becomes grainy or looks like it is splitting while whipping, stop immediately. Transfer it to a saucepan and gently melt it over low heat until smooth, then rechill and try again.
- This cake is actually better on day 2. The crumb firms up beautifully overnight and the flavours deepen. If you can bake it the day before serving, do so.
Variations
- Lemon and white chocolate: Replace the raspberry jam with a good-quality lemon curd and add the zest of one large lemon to the batter. Use fresh blueberries to decorate.
- Passionfruit version: Swap the raspberry jam for strained passionfruit pulp (about 4 passionfruits) stirred with 2 tbsp of icing sugar until the sugar dissolves, then swirl through the batter as directed.
- White chocolate and strawberry: Use a good seedless strawberry jam and decorate with fresh halved strawberries and white chocolate shavings for a classic pairing.
- Dark chocolate version: Replace the white chocolate in the cake batter with an equal weight of 70% dark chocolate and use the same raspberry jam swirl. The frosting can be made with dark chocolate ganache instead: use 300g dark chocolate with 300ml warm cream, chill, and whip the same way.
Troubleshooting & FAQ
My ganache frosting won’t whip up, it just stays liquid and loose.
The ganache is not cold enough. The cream and chocolate mixture needs to be thoroughly chilled, ideally for at least 4 hours, and the bowl and whisk attachments should also be cold (pop them in the freezer for 10 minutes before whipping). Return the ganache to the fridge for at least another hour and try again. If your kitchen is very warm, place the mixing bowl over a larger bowl filled with ice water while you whip. Also check that you used real white chocolate with cocoa butter, not compound white chocolate chips, as compound chocolate does not contain cocoa butter and will not set or whip properly.
The cake sank in the middle after baking.
This is most often caused by underbaking, which is easy to do with a dense mud cake since the top sets and looks done before the centre is fully cooked. Always test with a toothpick at the minimum bake time and ensure it comes out with only moist crumbs, not wet batter. It can also happen if the oven door was opened in the first 40 minutes of baking, causing the structure to collapse before it had set. Finally, check that your baking powder and baking soda are fresh, and that you measured them accurately.
The raspberry jam completely disappeared into the batter and I can’t see any swirls.
This happens when the jam is too thin or when you over-swirled it. Warm the jam just enough to make it pourable but not so much that it becomes watery. Use a spoon to drop blobs across the surface rather than pouring it in a thin stream, which spreads it too evenly. Then swirl with only 3 to 4 gentle strokes per pan. A jam with a slightly higher pectin content (often labelled ‘set’ or ‘firm’) tends to hold its shape better in a swirl.
My batter looks lumpy after I added the eggs to the chocolate mixture.
The chocolate mixture was still too warm when the eggs were added, causing them to partially cook and seize. Unfortunately, there is no easy fix for a severely scrambled batter. To prevent this, always check the temperature of the mixture before adding eggs: press your wrist against the side of the bowl and it should feel neutral or barely warm, not hot. If you notice only very slight lumpiness, you can try passing the batter through a fine-mesh sieve before adding the dry ingredients, which will catch any cooked egg bits.
The cake is very dense and gluey in the middle, even after the full bake time.
Mud cakes are naturally dense, but a gluey, underset centre usually means the oven temperature is running too hot, causing the outside to overbake before the centre is cooked. An oven thermometer is invaluable here since many home ovens run 10 to 25 degrees hotter or cooler than the dial indicates. If you suspect this, reduce the oven temperature by 15°F (about 8°C) and extend the baking time. Baking at a lower temperature for longer allows the heat to penetrate to the centre more gently and evenly.
Storage & Make-Ahead
- Storage: Store the finished cake covered in the refrigerator for up to 5 days. Because of the cream-based ganache frosting, it must be kept chilled. Remove slices from the refrigerator 20 to 30 minutes before serving to allow the ganache to soften and the flavour to bloom. Unfrosted cake layers can be stored wrapped tightly in plastic wrap at room temperature for 2 days, or frozen for up to 3 months. Thaw overnight in the refrigerator before frosting.
- Make-Ahead: The ganache frosting should ideally be made the night before, as it needs at least 4 hours to chill before it can be whipped. The cake layers can be baked up to 2 days ahead, wrapped tightly in plastic wrap, and kept at room temperature. The fully assembled and frosted cake can be made one day ahead and refrigerated until needed.
