Peanut Butter Slice (Low-carb, Low-Sugar, Gluten-Free)

Peanut butter lovers, this one is for you! Inspired by a light brownie (also known as blondie), this peanut butter slice is made with low-sugar and low-carb ingredients and is keto and gluten-free friendly. It’s satiating,  and high in protein and fibre, making it a great pre or post-workout snack or a nutritious dessert. Make with or without dark chocolate on top.

Peanut Butter Slice (Low-Carb, Gluten-Free, Low-Sugar)

Peanut Butter Slice

I love anything with peanut butter (or any nut butter, really) and I’ve always wanted to make a brownie-like slice using it as the main ingredient. I remember trying something similar in a cafe a while back and taking a mental note that I should recreate it for the blog.

The version that I tried was made with brown sugar but I really wanted to make a healthier recipe, so I researched if it was possible to get a sugar-free version and it turns out you can. 

Low-Carb Peanut Butter Slice

How To Make Peanut Butter Slice

This blondie slice recipe is very easy. All ingredients are low-sugar and low-carb friendly: sugar-free sweetener (more on that below), high-protein and fat peanut butter (crunchy and unsweetened brand), coconut flour, almond meal, coconut oil and eggs. A little splash of vanilla.

How to make peanut butter slice 1

Brown Sugar Alternative

You might be familiar with white sugar alternatives made with either stevia, xylitol or erythritol, which are sold as sugar-free, carb-free sweeteners. A blondie recipe usually calls for brown sugar as it has that lovely caramel-like aroma and flavour and I really wanted to keep that in this recipe. I found Sukrin Gold brown sugar sweetener on Amazon and ordered a packet to give it a try.

Sukrin Gold is a natural sugar substitute with less than 1 kcal per teaspoon and the studies show that it doesn’t affect blood sugar or insulin levels in the body. This means that it can be safely used by diabetic or those following a keto or low-carb diets.

This sweetener is made of erythritol, which is made from glucose extracted from non-GM corn starch, plus some stevia and malt extract (gluten-free). It has a golden brown colour and a similar texture to fine brown sugar. It smells very similar and when I tasted it by itself, it did have a resemblance to the caramelised sugar. So that’s what I used in this recipe and it worked well. 

You can, of course, deviate and use another type of sugar-free sweetener or coconut sugar. 

How to make low-carb peanut butter slice 2

The batter is whisked and transferred to a brownie baking tin. I broke a couple of squares of very dark chocolate (90% cocoa) and sprinkled over the top. You could also use some chocolate buttons or use melted chocolate to make a few swirls through the batter. You can leave it out, too. 

Baking takes about 20 minutes until the centre is only just set. Once you remove the tin from the oven, the slice will continue to cook slightly and set while it’s cooling down. Slice it into squares and enjoy! It has that yummy peanut butter flavour with warm, caramel tones of brown sugar and coconut.

Peanut Butter Blondie Slice
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Low-Carb Peanut Butter Slice

Peanut Butter Slice (Keto, Gluten-Free)

  • Author: Irena Macri
  • Prep Time: 15 minutes
  • Cook Time: 20 minutes
  • Total Time: 35 minutes
  • Yield: 12 slices 1x
  • Category: Dessert
  • Method: Baked
  • Cuisine: American
  • Diet: Diabetic
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This blondie inspired peanut butter slice is made with sugar-free sweetener and low-carb flours for a healthy, keto-friendly and gluten-free dessert or a snack.



1 cup peanut butter (crunchy, unsweetened)

1/4 cup coconut oil (measured in slightly softened solid form)

1/2 cup Sukrin Gold brown sugar alternative (see notes for substitutes)

3 eggs

1.5 tablespoons vanilla

2/3 cup (100 g) almond meal/flour

2 tablespoons coconut flour

A pinch of salt

1 teaspoon baking powder (gluten-free)

2 squares, 90% Lindt chocolate broken into pieces or dark chocolate buttons


  • Preheat the oven to 180 C/355 F.
  • Melt peanut butter and coconut oil (you can do this in a hot oven, microwave or over low heat on the stove). Transfer to a large mixing bowl, add the brown sugar alternative and combine with a spatula.
  • Add eggs and vanilla and whisk together.
  • Add the flours, salt and baking powder and mix through.
  • Transfer to a baking tin (10.5 x 8″) lined with parchment paper. Flatten the top with a spatula. Insert a few pieces of dark chocolate or chocolate buttons. You can also melt the dark chocolate first and drizzle it over the top, then use a knife or a skewer to swirl it through the batter.
  • Bake for 20 minutes, until just set. Remove from the oven and cool for 10 minutes before removing from the tray. Slice into even squares.


Sugar-alternatives:  In this recipe, I am using Surkin Gold, which is a low-cal, low-carb brown sugar alternative. It has a similar texture, aroma and taste to light brown sugar but is in fact a mix of erythritol, which is made from fermented glucose extracted from non-GM corn starch, stevia, and gluten-free malt. You can use regular white sugar-alternative powder (I prefer erythritol and stevia mix for the least aftertaste). Alternatively, coconut sugar would also work well as a low-GI sugar substitute.

Storing: Store for 4-5 days in an airtight container or for 7-8 days in the refrigerator.

Freezing: This peanut butter blondie slice can also be frozen for up to 3 months. Slice it first and store in Ziploc bag or container with a lid. Defrost overnight and reheat in the oven or microwave slightly before consuming.


  • Serving Size: 1 blondie square
  • Calories: 296
  • Sugar: 2 g
  • Sodium: 160.6 mg
  • Fat: 23.4 g
  • Saturated Fat: 5.5 g
  • Carbohydrates: 11.4 g
  • Fiber: 4.2 g
  • Protein: 11.2 g
  • Cholesterol: 30.7 mg

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Save This Peanut Butter Slice To Pinterest

Peanut Butter Slice (Low-Carb, Gluten-Free, Low-Sugar)
Irena Macri
By Irena Macri

About the author: Hi, I’m Irena Macri. I share easy, delicious recipes with a healthy twist. I’ve been food blogging for over 10 years and have a Diploma in Nutrition & Weight Management. I believe in a balanced diet with an occasional cookie and cheesy pasta. More about me here. Sign-up for my newsletter and subscriber freebies.

PS. Some posts contain affiliate links, which means I receive a small commission for purchases made through these links.

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