Head to your kitchen right now and make this Keto Peanut Butter Sheet Cake. With a creamy layer of sugar-free frosting, it’s a peanut butter lover’s dream dessert.
I confess that I was a sheet cake virgin until I met my husband. I guess you can chalk that up to the great cultural divide known as the 49th parallel. He once waxed poetic about his mum’s Texas Sheet Cake and I looked at him with that blank expression that says “I do not understand the words that are coming out of your mouth”.
After experiencing this classic dessert for myself, I quickly came to understand the allure. I created a Keto Texas Sheet Cake that has met with approval from almost everyone, including dyed-in-the-wool Texans!
And of course I had to make a peanut butter sheet cake. Trust me, you will be SO glad I did!
Why you must try this recipe
There’s a lot to love about this Keto Peanut Butter Cake. It’s easy to make and assemble, because you just frost it and serve it right out of the pan. What might be viewed as a gauche shortcut for other cakes is perfectly acceptable when it comes to sheet cake.
And it feeds a crowd too, so it’s perfect for parties and get togethers. You can also portion it up and freeze it for easy desserts any old time.
But my favourite part about sheet cake? It has an excellent frosting-to-cake ratio! You don’t end up with overly thick layers of sponge and paltry thin layers of frosting. A perfect proportion in every bite.
“HOLY TOLEDO! THIS IS AMAZINGLY FANTASTICALLY supercalifragilistically YUUUUUUMMMMMMYYYYYYYYYY!!!!!! Remember the Partridge Family? “Well I think I love you…” ??????❤️” — Nancy
“AWESOME!! I gotta tell you I have been wholey disappointed in low carb deserts especially baked goods. It was too far off the original, to artificially sweet typically that it wasn’t even worth it . THIS however was REVOLUTIONARY!!! Thank you for posting it on Instagram and making me enjoy a cake again without the carb guilt.” — A.
“Amazing cake!!! I am from Texas and very accustomed to sheet cake!!! You did a fabulous job????????I am making this one for the second time…..I have 7 children and they all love it!! Even those who have no idea its grain and sugar free enjoyed it????Great work as always!!!!” — DJ
Ingredients you need
- Keto flours: I use a combination of almond flour and coconut flour for a light consistency with fewer carbs.
- Protein powder: I use whey protein isolate to help the cake rise better. You can also use egg white or plant-based protein, but collagen protein will not work
- Creamy peanut butter: Use a good all-natural creamy peanut butter. My favorites are Santa Cruz and Wild Friends.
- Butter: Both the cake and the frosting used unsalted butter.
- Sweetener: The cake takes a granular sweetener and the frosting uses powdered sweetener. I use Swerve for both. See the Expert Tips section for more sweetener options.
- Cream cheese: Using some cream cheese in the frosting makes it extra rich and creamy.
- Heavy cream: You will need some cream to help thin the frosting to a spreadable consistency. .
- Peanuts: I like to garnish the cake with some chopped salted peanuts.
- Kitchen staples: Eggs, vanilla extract, baking powder and salt
1. Beat the wet ingredients: In a large bowl, beat together the peanut butter and butter until well combined. Beat in the sweetener, and then beat in eggs and vanilla extract.
2. Add the dry ingredients: All at once, add the almond flour, coconut flour, protein powder, baking powder and salt. Beat until combined.
3. Thin out the batter: Beat in water a little at a time until the batter is a spreadable consistency.
4. Bake the cake: Spread the batter in a greased 10×15 inch rimmed sheet pan and smooth the top. Bake at 325ºF for 18 to 22 minutes, until edges are golden brown and cake is set. Remove and let cool in pan.
5. Prepare the frosting: Beat the cream cheese, butter and peanut butter in a large bowl until well combined. Beat in the sweetener, cream and vanilla extract until mixture is smooth.
6. Frost the cake: Spread the frosting evenly over the cooled cake. Sprinkle with chopped peanuts.
If you grease the pan well, the cake should come out of it fairly easily. But you can also line with parchment if you need to. Grease the parchment paper as well.
I like using a jelly roll pan for sheet cakes, which is 10×15 inches. Keep in mind that if you use an 11×17 pan, the cake will be much thinner and will bake faster.
Sweetener Options: You can use almost any granular sweetener in the cake, but do note that allulose may cause it to brown quite quickly. You can also cut back on the Swerve to half a cup and add additional sweetness with stevia or monk fruit extract.
For the frosting, you do need a powdered sweetener to give it the right consistency.
Frequently Asked Questions
Sheet cakes differ from most other cakes as they are baked in a large shallow pan (a sheet pan or a baking sheet). They have a single thin layer of cake with a layer of frosting on top. This gives them a wonderful cake-to-frosting ratio.
This low carb peanut butter sheet cake recipe has 7.9g of carbs and 2.5g of fiber per serving. That comes to 5.4g net carbs per serving.
Store the cake in an airtight container on the counter for up to 3 days or in the fridge for up to a week. To freeze, I recommend cutting into individual portions first and setting them spaced out on a cookie sheet. Freeze until firm and then place in a container. This way, they won’t stick together!
More keto cakes you’ll love!
Peanut Butter Sheet Cake Recipe
- Preheat the oven to 325ºF and grease a 10×15 inch rimmed sheet pan well. You can use 11×17 but your cake will be thinner and will bake through much faster.
- In a large bowl, beat together the peanut butter and butter until well combined. Beat in the sweetener, and then beat in eggs and vanilla extract.
- All at once, add the almond flour, coconut flour, protein powder, baking powder and salt. Beat until combined.
- Beat in water a little at a time until the batter is a spreadable consistency.
- Spread the batter in the prepared pan and smooth the top. Bake for 18 to 22 minutes, until edges are golden brown and cake is set. Remove and let cool in pan.
- In a large bowl, beat the cream cheese, butter and peanut butter until well combined. Beat in the sweetener, cream and vanilla extract until mixture is smooth.
- Spread the frosting evenly over cooled cake. Sprinkle with chopped peanuts.