This keto peanut butter fudge hits that sweet spot between creamy and indulgent without the sugar crash. It’s simple to make, requires no oven time, and sets up beautifully in the fridge. If you love peanut butter, this is the kind of treat that makes sticking to low-carb eating feel easy.
With just a handful of ingredients, you’ll have a dessert that tastes like classic fudge, minus the carbs. Keep a batch on hand for snacks, desserts, or those late-night cravings.
Ingredients
Method
- Prep your pan: Line an 8x8-inch pan with parchment, leaving overhang on two sides for easy lifting. For thicker fudge, use a smaller pan.
- Warm the base: In a small saucepan over low heat, add 1 cup creamy natural peanut butter and 1/2 cup unsalted butter. Stir until smooth and fully melted. Keep the heat low to avoid scorching.
- Sweeten and flavor: Whisk in 1/2 to 3/4 cup powdered erythritol or allulose, 2–3 tablespoons heavy cream, 1 teaspoon vanilla extract, and a pinch of salt. Adjust sweetener to taste. If using allulose, note it’s slightly less sweet than erythritol blends.
- Smooth it out: Continue whisking over low heat for 1–2 minutes until glossy and uniform. If it looks oily, take it off the heat and whisk vigorously to emulsify. A quick blitz with an immersion blender can help.
- Add extras: Fold in any add-ins like 1/4 cup chopped peanuts or a handful of sugar-free chocolate chips.
- Pour and level: Spread the mixture into the lined pan. Tap the pan gently on the counter to release air bubbles and smooth the top.
- Optional chocolate layer: Melt 1/2 cup sugar-free chocolate chips with 1 teaspoon coconut oil. Pour over the peanut layer and spread thinly.
- Chill to set: Refrigerate for 1–2 hours, or freeze for 25–30 minutes, until firm but sliceable.
- Slice and store: Lift out using the parchment and cut into 16–25 squares. For clean cuts, warm a knife under hot water, wipe it dry, and slice.
What Makes This Recipe So Good
- Quick and no-bake: You only need a few minutes on the stovetop, then let the fridge do the rest.
- Ultra creamy texture: Butter and peanut butter come together for a silky, melt-in-your-mouth bite.
- Low in carbs, high in flavor: Sweetened with a keto-friendly sweetener, so you can enjoy dessert without the sugar.
- Easy to customize: Add vanilla, chopped nuts, or a swirl of chocolate to make it your own.
- Small-batch friendly: Scales up or down without fuss.
Shopping List
- Natural peanut butter (unsweetened, no added sugar; creamy works best)
- Unsalted butter (or coconut oil for dairy-free)
- Powdered erythritol or allulose (powdered blends dissolve best)
- Heavy cream (optional but adds richness; swap with coconut cream for dairy-free)
- Vanilla extract
- Fine sea salt (skip if your peanut butter is salted)
- Optional add-ins: chopped roasted peanuts, sugar-free chocolate chips, flaky salt, cinnamon
- Optional chocolate layer: sugar-free chocolate chips and a teaspoon of coconut oil
Step-by-Step Instructions
- Prep your pan: Line an 8×8-inch pan with parchment, leaving overhang on two sides for easy lifting. For thicker fudge, use a smaller pan.
- Warm the base: In a small saucepan over low heat, add 1 cup creamy natural peanut butter and 1/2 cup unsalted butter.
Stir until smooth and fully melted. Keep the heat low to avoid scorching.
- Sweeten and flavor: Whisk in 1/2 to 3/4 cup powdered erythritol or allulose, 2–3 tablespoons heavy cream, 1 teaspoon vanilla extract, and a pinch of salt. Adjust sweetener to taste.
If using allulose, note it’s slightly less sweet than erythritol blends.
- Smooth it out: Continue whisking over low heat for 1–2 minutes until glossy and uniform. If it looks oily, take it off the heat and whisk vigorously to emulsify. A quick blitz with an immersion blender can help.
- Add extras: Fold in any add-ins like 1/4 cup chopped peanuts or a handful of sugar-free chocolate chips.
- Pour and level: Spread the mixture into the lined pan.
Tap the pan gently on the counter to release air bubbles and smooth the top.
- Optional chocolate layer: Melt 1/2 cup sugar-free chocolate chips with 1 teaspoon coconut oil. Pour over the peanut layer and spread thinly.
- Chill to set: Refrigerate for 1–2 hours, or freeze for 25–30 minutes, until firm but sliceable.
- Slice and store: Lift out using the parchment and cut into 16–25 squares. For clean cuts, warm a knife under hot water, wipe it dry, and slice.
Keeping It Fresh
- Fridge: Store in an airtight container for up to 10 days.
Keep layers separated with parchment if stacking.
- Freezer: Freeze for up to 3 months. Wrap pieces individually, then place in a freezer bag. Thaw in the fridge for 20–30 minutes before eating.
- Serving temp: This fudge tastes best slightly chilled.
At warm room temps, it can soften quickly.
Benefits of This Recipe
- Low-carb and keto-friendly: Uses a sugar substitute and peanut butter for a treat that fits your macros.
- Healthy fats: Satiating fats help keep you full and satisfied.
- No baking required: Ideal for hot days, busy schedules, or quick cravings.
- Customizable sweetness: You control the sweetener type and amount.
- Minimal ingredients: Pantry staples come together fast.
Pitfalls to Watch Out For
- Hidden sugars: Some peanut butters contain added sugar or fillers. Choose natural, unsweetened varieties.
- Gritty texture: Granulated sweeteners don’t dissolve well. Use powdered sweetener for a smooth fudge.
- Oily separation: Overheating can cause the fat to separate.
Keep the heat low and whisk steadily.
- Too soft: If your fudge doesn’t set, reduce the cream slightly or add 1–2 tablespoons more powdered sweetener.
- Too sweet or cooling effect: Erythritol can have a cooling aftertaste. Allulose or a blend with monk fruit can taste smoother.
Variations You Can Try
- Chocolate swirl: Melt a few tablespoons of sugar-free chocolate and swirl into the top with a toothpick.
- Crunchy peanut: Use crunchy peanut butter or fold in chopped roasted peanuts for texture.
- Cinnamon roll: Add 1/2 teaspoon cinnamon and a pinch of nutmeg, then drizzle with a thin cream cheese glaze (sweetened with powdered erythritol).
- Salted fudge: Sprinkle flaky sea salt on top right before chilling for a sweet-salty combo.
- Nut-free swap: Use sunflower seed butter for a peanut-free version. Taste and adjust sweetener, as it can be slightly more bitter.
- Dairy-free: Replace butter with coconut oil and heavy cream with coconut cream.
Expect a slightly firmer set from the coconut oil.
FAQ
Can I use chunky peanut butter?
Yes. Chunky peanut butter works, but the texture will be less silky. If you want the best of both worlds, use creamy peanut butter and fold in chopped peanuts at the end.
What sweetener works best?
Powdered allulose gives the smoothest, least gritty texture and no cooling effect.
Powdered erythritol or monk fruit–erythritol blends also work, but you may notice a slight cooling sensation.
How many carbs are in a piece?
It varies by brand and portion size, but generally you can expect around 2–3 net carbs per piece if cut into 25 squares. Always calculate based on your exact ingredients.
My fudge is oily. Can I fix it?
Usually, yes.
Take it off the heat and whisk vigorously to re-emulsify. An immersion blender can quickly bring it back together. If needed, whisk in 1–2 teaspoons of heavy cream.
Can I make it without dairy?
Absolutely.
Use coconut oil in place of butter and coconut cream instead of heavy cream. The flavor leans slightly coconut, but it pairs nicely with peanut butter.
How long does it take to set?
In the fridge, about 1–2 hours. In the freezer, 25–30 minutes.
The chocolate layer, if added, can take a little longer to firm up.
Does this travel well?
It’s fine for a short trip with an ice pack. At warm room temperature, it softens, so keep it chilled until serving.
Can I use a different nut butter?
Yes. Almond butter, cashew butter, or sunflower seed butter all work.
Choose unsweetened versions and taste as you go, since sweetness and salt levels vary.
Wrapping Up
Keto peanut butter fudge is one of those back-pocket recipes that feels special but takes almost no effort. With just a few ingredients and a little chill time, you’ll have a creamy, satisfying treat ready whenever a craving hits. Keep the base recipe handy, then play with flavors and textures to make it yours. Whether you’re new to keto or a seasoned pro, this fudge delivers big flavor without the sugar.
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