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Sugar Free Peanut Butter Fudge

Fudge without sugar? It’s not only possible–it’s unbelievably delicious! Satisfy your sweet tooth with Sugar Free Peanut Butter Fudge. This easy fudge is rich and creamy, without the sugar crash!

If you love peanut butter, be sure to try our sugar free Buckeyes too! Or give these delicious Keto Peanut Butter Cookies a whirl next time you crave peanut butter!

Stack of peanut butter fudge squares.

Why This Recipe Works

I can live without a lot of things. Fudge isn’t one of them.

So when I started living a life without added sugars, creating a sugar free fudge recipe was a top priority!

  • This Low Carb Peanut Butter Fudge recipe uses erythritol, a naturally occurring sugar substitute, for sweetness.
  • Get an extra boost of protein in your dessert with the peanut butter and collagen powder in this recipe.
  • No unpleasant after taste or chalky texture. It tastes like your favorite old fashioned creamy peanut butter fudge–only it won’t mess with your blood sugar.

You only need six ingredients and one bowl to whip up this fudge. An easy no bake sugar free treat! Our sugar free chocolate pudding is so easy too!

Ingredient Notes

Ingredients needed for keto peanut butter fudge.
  • Creamy peanut butter. Make sure to use a peanut butter with no added sugars.
  • Erythritol. This calorie free sugar substitute can be found in the natural foods section of many grocery stores. Monkfruit powder works in this recipe too!
  • Collagen Powder. Substitute whey powder or your other favorite protein powder if preferred (or use a combination).
  • Butter. I always choose unsalted in my baking, and Kerrygold is a delicious option!

Easy Instructions

Clear glass mixing bowl with peanut butter fudge ingredients.
  1. First, combine all the ingredients in your mixing bowl. Stir well until smooth and well blended.
  2. Pour it into a 8-inch square dish lined with parchment paper.
  3. Place the dish in the freezer for 1 hour. It’ll firm up similar to the consistency of traditional fudge.

When ready to eat, slice into squares and enjoy!

Tips and Tricks

  • The fudge batter is very soft before freezing. Resist the urge to add more ingredients to firm it up. It’ll solidify as it freezes.
  • If you freeze sugar free peanut butter fudge for longer than an hour, let it sit at room temperature for 5 minutes before slicing.
  • Store any leftover fudge (as if) in an airtight container in the freezer.
Slices of keto peanut butter fudge.

Recipe FAQs

Is this fudge recipe Keto friendly?

Yes, this sugar free peanut butter fudge is suitable for Keto diets.

Can I make this with chunky peanut butter instead?

I don’t recommend using chunky peanut butter here. The nuts will affect how the fudge holds together. If you want some crunch in your fudge, you could sprinkle chopped peanuts on top before freezing!

Could I make this with another kind of nut butter?

Yes, this sugar free fudge recipe would work with almond butter, cashew butter or any other nut butter you like! Just make sure to use a creamy variety with no added sugars.

Why is my fudge soft and runny?

The batter is supposed to be soft when you first combine the ingredients. Make sure to let the fudge freeze for a full hour. If it is still too soft to cut, let it sit in the freezer for a bit longer. If your home freezer gets opened and closed frequently while the fudge is setting, it may take longer to firm up.

What should I do if my fudge is too hard to cut?

Fudge that is frozen for a long time will be extra solid. Just let it sit at room temperature for a few minutes until it’s soft enough to slice.

More Keto Friendly Recipes

Squares of peanut butter fudge.

Sugar Free Peanut Butter Fudge Recipe

Yield: 16 pieces
Prep Time: 5 minutes
Freeze Time: 1 hour
Total Time: 1 hour 5 minutes

Fudge without sugar? It's not only possible--it's unbelievably delicious! Satisfy your sweet tooth with Sugar Free Peanut Butter Fudge. This easy fudge is rich and creamy, without the sugar crash!


  • 1 cup creamy peanut butter
  • ½ cup collagen powder
  • ⅓ cup unsalted butter
  • ⅓ cup powdered erythritol (or monkfruit)
  • 1 teaspoon vanilla extract
  • ¼ teaspoon kosher salt


    1. In a mixing bowl, combine all of the ingredients together until smooth and well blended.
    2. Pour the fudge mixture into a parchment paper lined 5x7-inch dish, one of the 3-cup rectangular pyrex dishes works great for this!
    3. Freeze for 1 hour before enjoying.


  • The fudge batter is VERY soft, you do not need to add extra ingredients to thicken it, it will firm up once frozen.
  • After one hour in the freezer, the fudge will have a consistency similar to a traditional piece of fudge.
  • Ifin the freezer for more than 1 hour, I recommend letting the pieces sit at room temperature for about 5 minutes to soften before eating.
  • You could use protein powder or whey powder in place of collagen, or use a combination of protein powder and collagen.
  • Make sure to choose a no sugar added peanut butter.
Nutrition Information:
Yield: 16 Serving Size: 1 square
Amount Per Serving:Calories: 143Total Fat: 12gSaturated Fat: 4gTrans Fat: 0gUnsaturated Fat: 6gCholesterol: 10mgSodium: 107mgCarbohydrates: 4gFiber: 1gSugar: 1gProtein: 7g

Peanut Butter Fudge without the sugar and carbs! Packed with protein and peanut butter flavor, this rich creamy keto fudge recipe makes any day sweeter.


Tuesday 19th of September 2023

I want to make this for Festival. If I keep it on ice will it be ok? Also will It have to be eaten right away? TY

David Overall

Saturday 9th of September 2023

Can you substitute the collagen?


Tuesday 29th of August 2023

I have monk fruit sweetener but it's not powdered, it's granulated. Will that work or will it effect the texture? Thank you for the recipe, we can't wait to try it.

Gina White

Sunday 18th of December 2022

This would make a great Xmas gift for my low carb friends, so doing this!!

Ted Clark

Saturday 10th of December 2022

Sure looks delicious, showed it to my wife and you should have seen the expression on her face. Surely going to try it..

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