Fudgy Erythritol Peanut Butter Blondies

Name: Fudgy Erythritol Peanut Butter Blondies
Prep time: 10 min
Cook time: 25 min
Total time: 40 min
Yield: one 8x8-inch pan, cut into 16 squares
Cuisine: American
Ingredients: 260 g natural creamy peanut butter (about 1 cup), well stirred, no added sugar; 120 g granulated erythritol (about 1/2 cup plus 2 tbsp); 30 g powdered erythritol (about 1/4 cup), sifted; 2 large eggs, at room temperature; 60 g unsalted butter (about 4 tbsp), melted and slightly cooled; 2 tsp pure vanilla extract; 60 g almond flour, blanched and finely ground (about 1/2 cup plus 1 tbsp); 1 tsp baking powder; 0.5 tsp fine sea salt; 60 g sugar-free chocolate chips (about 1/3 cup), optional but recommended; Flaky sea salt for topping, optional

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Close your eyes and imagine pulling a tray of golden, glossy-topped blondies from the oven, the scent of toasted peanut butter and warm vanilla curling through your kitchen. Now imagine that they are completely sugar-free, low in carbs, and will not send your blood sugar on a rollercoaster ride. That is exactly what these erythritol peanut butter blondies deliver. Dense and fudgy in the center with slightly crisp edges, they scratch every blondie itch without a single gram of refined sugar.

What sets this recipe apart is the combination of granulated erythritol and a small amount of powdered erythritol, which together mimic the texture of brown sugar blondies far better than using one form alone. The granulated erythritol creates structure and a subtle caramel-like depth when it melts during baking, while the powdered version dissolves completely into the batter so you never get that gritty, cooling aftertaste that plagues so many sugar-free bakes. A generous measure of natural peanut butter (the drippy, stir-before-you-use kind) keeps these blondies moist and chewy even after they cool.

These blondies sit solidly in the easy-to-medium range of difficulty, making them a fantastic weekend bake for anyone managing diabetes, eating low-carb, or simply trying to cut refined sugar without sacrificing joy. You need one bowl, a whisk, and about 35 minutes from start to finish. They are also a brilliant make-ahead treat because they actually get chewier and more flavorful on day two.

Prep: 10 minutesTotal: 40 minutes (plus 15 minutes cooling)Yield: one 8×8-inch pan, cut into 16 squaresDifficulty: ★☆☆ EasyOccasion: Everyday Treat

✓ Vegetarian✓ Gluten-Free✓ Sugar-Free

Servings:

16

servings

Ingredients

260 gnatural creamy peanut butter (about 1 cup), well stirred, no added sugar
120 ggranulated erythritol (about 1/2 cup plus 2 tbsp)
30 gpowdered erythritol (about 1/4 cup), sifted
2 largeeggs, at room temperature
60 gunsalted butter (about 4 tbsp), melted and slightly cooled
2 tsppure vanilla extract
60 galmond flour, blanched and finely ground (about 1/2 cup plus 1 tbsp)
1 tspbaking powder
0.5 tspfine sea salt
60 gsugar-free chocolate chips (about 1/3 cup), optional but recommended
—Flaky sea salt for topping, optional

Ingredient Substitutions

granulated erythritol

Equal weight of a granulated monk fruit and erythritol blend (such as Lakanto Golden) for a warmer, more brown-sugar-like flavor
Equal weight of allulose, which gives an even fudgier texture but the blondies will be slightly darker and stickier on the surface

powdered erythritol

Make your own by blending granulated erythritol in a high-speed blender or spice grinder for 30 seconds until fine
Equal weight of powdered monk fruit and erythritol blend

natural creamy peanut butter

Natural almond butter for a milder, slightly sweeter flavor. The texture will be nearly identical.
Sunflower seed butter for a nut-free version. The blondies may turn slightly green due to a reaction between sunflower seeds and baking powder, but this is harmless.

unsalted butter

Equal weight of refined coconut oil (melted) for a dairy-free version. Use refined, not virgin, to avoid a coconut flavor.
Equal weight of ghee for a richer, slightly nuttier flavor

eggs

2 flax eggs (2 tbsp ground flaxseed mixed with 6 tbsp water, rested 10 minutes) for a vegan version. The blondies will be slightly more dense and less chewy.
2 tablespoons of unsweetened applesauce per egg as a lighter option, though structure will be softer

almond flour

Equal weight of oat flour for a nut-free option, though this will increase the carb count and raise the glycemic load
Equal weight of sunflower seed flour (ground sunflower seeds) for nut-free and low-carb

Instructions

🔧 Equipment

🟫8×8-inch metal baking pan

🟫7-inch square or round metal baking pan (for air fryer method)

📄parchment paper

🥣large mixing bowl

🍴rubber spatula

🌀whisk

🔵wire cooling rack

🔪sharp chef’s knife

📡microwave-safe mug or 8 oz ramekin (for microwave method)

🔵fine mesh sieve or sifter

⚖️kitchen scale (strongly recommended)

Prep: 10 minutes
Bake: 22 to 25 minutes at 325°F (163°C)
Total: 40 minutes plus 15 minutes cooling

Preheat your oven to 325°F (163°C). Line an 8×8-inch metal baking pan with parchment paper, leaving an overhang on two sides for easy lifting. Lightly grease the exposed sides of the pan.
In a large mixing bowl, whisk together the peanut butter, melted butter, granulated erythritol, and powdered erythritol until smooth and well combined, about 1 minute. The mixture will look thick and glossy.
Add the eggs one at a time, whisking well after each addition. Add the vanilla extract and whisk until the batter is completely smooth and slightly lighter in color, about 30 seconds more.
Add the almond flour, baking powder, and fine sea salt. Switch to a rubber spatula and fold until just combined, being careful not to overmix. If using sugar-free chocolate chips, fold them in now.
Transfer the batter to the prepared pan and spread it into an even layer using the spatula or the back of a spoon dampened with water. The batter will be thick. Scatter flaky sea salt over the top if using.
Bake for 22 to 25 minutes, until the top is set and matte (not shiny), the edges are just pulling away from the pan, and a toothpick inserted in the center comes out with a few moist crumbs but no wet batter. Do not overbake. Erythritol-sweetened blondies firm up considerably as they cool.
Let the blondies cool in the pan on a wire rack for at least 15 minutes before lifting out and slicing. For the cleanest cuts, refrigerate for 30 minutes before slicing with a sharp knife.

Prep: 10 minutes
Bake: 18 to 20 minutes at 300°F (150°C)
Total: 35 minutes plus 15 minutes cooling

The air fryer produces blondies with a slightly crispier top crust and a very fudgy center. Works best in a 6-quart or larger air fryer. Use a 7-inch square or round baking pan that fits your basket.

Line a 7-inch square or 7-inch round metal baking pan with parchment paper and lightly grease. Prepare the blondie batter exactly as written in Steps 2 through 5 of the oven method.
Preheat your air fryer to 300°F (150°C) for 3 minutes. The lower temperature is critical here because air fryers circulate heat aggressively, and a higher temperature will overbrown the exterior before the center sets.
Spread the batter into the prepared pan in an even layer. Place the pan in the air fryer basket. If your basket has a wire bottom, set the pan on a small piece of foil to prevent uneven heat from below.
Air fry for 18 to 20 minutes. At the 15-minute mark, check the blondies. The top should look matte and set. If the edges are browning very quickly, loosely tent a small piece of foil over the top for the remaining minutes.
The blondies are done when the center is just set and a toothpick inserted in the middle comes out with moist crumbs. They will look slightly underdone, but they firm up as they cool. Let cool in the pan for 15 minutes, then lift out and slice.

Prep: 10 minutes
Bake: 60 to 90 seconds
Total: 10 minutes

This method makes 2 individual blondies in a mug or small ramekin. Scale down the ingredient amounts to 1/8 of the full recipe. Perfect for a quick single-serve treat without heating the oven.

For one generous serving, combine 32g (about 2 heaping tablespoons) natural peanut butter, 15g granulated erythritol, 4g powdered erythritol, 1 egg yolk (not the whole egg, which can turn rubbery), 1 teaspoon melted butter, and 1/4 teaspoon vanilla in a microwave-safe mug or ramekin (at least 8 oz capacity). Stir well with a fork.
Add 8g (about 1 tablespoon) almond flour, a small pinch of baking powder, and a pinch of salt. Stir until smooth. Fold in a few sugar-free chocolate chips if desired.
Microwave on 50% power (medium) for 60 seconds. Check the center: it should look just barely set on top but not dry. If still very wet and glossy, microwave in 10-second bursts at 50% power until the surface is just set.
Do not microwave on full power, as this will create a rubbery, dry texture. The blondie will continue cooking from residual heat after you remove it. Let it rest for 2 minutes before eating directly from the mug, or invert onto a small plate.

Nutrition Per Serving

Per 1 serving (makes one 8×8-inch pan, cut into 16 squares)

148Calories

4gCarbs

1gSugar

13gFat

5gProtein

Glycemic Load2Low

Low0–10

Medium11–19

High20+

Erythritol has a glycemic index of 0 and is not metabolized by the body in the same way as sugar, contributing negligible calories and no measurable impact on blood glucose or insulin levels. The net carbs per serving are approximately 3g, coming primarily from almond flour and peanut butter.

Sweetener: erythritol

Why This Recipe Works

The real challenge with sugar-free blondies is replicating what sugar actually does in a traditional recipe, and it does a lot. Sugar is hygroscopic, meaning it absorbs and retains moisture, which is what makes blondies chewy rather than dry and cakey. Erythritol behaves similarly but is slightly less hygroscopic, which is why this recipe compensates with a high ratio of peanut butter and a full measure of butter. Both are fat-rich ingredients that coat the almond flour particles and trap moisture in the baked crumb, delivering that signature dense, fudgy interior even without refined sugar.

Using two forms of erythritol, granulated and powdered, is a deliberate technique. Granulated erythritol does not fully dissolve at room temperature the way sugar does, and undissolved crystals can create a gritty or sandy texture. By sifting powdered erythritol into the batter alongside granulated, you ensure that the majority of the sweetener is fully integrated, resulting in a smoother crumb. The powdered form also helps bind the batter and contributes to a slightly shiny, set top crust. Meanwhile, the granulated erythritol adds gentle structure and a pleasant chew.

Almond flour replaces all-purpose flour here, keeping the glycemic load very low and adding a subtle richness. Because almond flour contains no gluten, there is no risk of over-developing tough proteins in the batter. This also means you want to be careful not to overbake these blondies. Without gluten structure, they will seem very soft when they come out of the oven, which is correct. They firm up dramatically as they cool to room temperature, and even more so when refrigerated. If your blondies come out crumbly or dry, the oven temperature was likely too high or they baked a few minutes too long. Start checking at the 20-minute mark and pull them when the toothpick shows moist crumbs.

Baker’s Tips

Stir your peanut butter thoroughly before measuring. The separated oil on top, once mixed back in, is critical for moisture in these blondies.
Use a metal 8×8 pan rather than glass. Metal conducts heat more evenly and produces better-set edges. Glass pans retain heat and can lead to uneven baking with erythritol.
Do not substitute powdered sugar or other sweeteners with different volume-to-weight ratios without adjusting amounts by weight.
The blondies will look slightly underdone when you pull them from the oven. That is intentional. Trust the toothpick test and the cooling process.
For the cleanest, bakery-style cuts, refrigerate the cooled blondies for 30 minutes and use a sharp knife wiped clean between each cut.
Bring eggs to room temperature by setting them in a bowl of warm water for 5 minutes. Cold eggs can cause the peanut butter and butter mixture to seize slightly.

Variations

Chocolate swirl: Drop 3 tablespoons of melted sugar-free dark chocolate over the batter in the pan and use a toothpick to swirl it through before baking.
Crunchy peanut butter version: Use natural crunchy peanut butter instead of creamy and add 30g (about 3 tablespoons) of roughly chopped roasted peanuts folded into the batter.
Coconut and peanut butter: Fold in 30g (about 1/3 cup) of unsweetened shredded coconut for a chewy tropical twist.
Espresso blondies: Add 1 teaspoon of instant espresso powder to the batter with the dry ingredients for a mocha-peanut butter flavor.

Troubleshooting & FAQ

My blondies came out crumbly and dry. What went wrong?

This is almost always caused by overbaking. Erythritol-sweetened baked goods continue to firm up significantly as they cool, so what looks underdone in the oven is often perfectly set at room temperature. Start checking at 20 minutes and pull the blondies as soon as the toothpick shows just moist crumbs. Oily peanut butter separation (from not stirring the jar well) can also affect texture, so make sure your peanut butter is fully emulsified before measuring.

I notice a cold, cooling sensation when I eat these. Is something wrong?

Nothing is wrong with your blondies. This is a known characteristic of erythritol called a cooling effect, caused by the sweetener’s negative heat of solution, meaning it absorbs heat from your mouth as it dissolves. It is more noticeable when the blondies are eaten cold or when erythritol is used in large quantities. To minimize it, serve the blondies at room temperature rather than cold, and make sure you are using the powdered erythritol as specified so crystals are fully dissolved.

My batter is extremely thick and hard to spread. Is that normal?

Yes, this batter is intentionally thick, much thicker than a traditional blondie batter made with flour. The combination of peanut butter and almond flour creates a dense, scoopable consistency rather than a pourable one. Use the back of a spoon or offset spatula dampened with a little water to spread it evenly into the pan. Do not be tempted to add liquid to thin the batter, as this will affect the final texture.

Can I double this recipe for a 9×13 pan?

Yes. Double all ingredients exactly and bake in a parchment-lined 9×13-inch metal pan. The bake time will increase to approximately 28 to 33 minutes at the same temperature. Start checking at 26 minutes. The center of a larger pan takes longer to set, so use the toothpick test rather than relying on time alone.

Why did my blondies stick even though I used parchment paper?

Parchment paper alone should prevent sticking, but make sure you are leaving an overhang on at least two sides so you can lift the whole slab out cleanly. If you greased only the parchment but not the exposed sides of the pan, the edges may stick to the unlined sides. Always lightly grease the bare pan sides as well. Let the blondies cool for the full 15 minutes before lifting, as they are fragile when hot.

Storage & Make-Ahead

Storage: Store blondies in an airtight container at room temperature for up to 3 days, or refrigerate for up to 1 week. They become even chewier and more fudge-like when cold. Freeze in a single layer on a baking sheet, then transfer to a zip-top freezer bag for up to 3 months. Thaw at room temperature for 20 minutes.
Make-Ahead: The batter can be made up to 24 hours ahead, covered tightly, and refrigerated. Let it sit at room temperature for 15 minutes before spreading into the pan and baking. Baked blondies improve in texture on day two, making them an ideal make-ahead treat for gatherings.