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.
Reader reviews
“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
Step-by-step directions
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.
Expert tips
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
Ingredients
Cake:
- 1/2 cup (113.5 g) butter, softened
- 1/4 cup (64.5 g) peanut butter
- 2/3 cup (136.5 g) Swerve Sweetener
- 3 large (3) eggs, room temperature
- 1 tsp vanilla extract
- 1 3/4 cups (196 g) almond flour
- 1/3 cup (36 g) unflavoured whey protein powder, (or egg white protein powder)
- 1/4 cup (30 g) coconut flour
- 2 1/2 tsp (2.5 tsp) baking powder
- 1/2 tsp (0.5 tsp) salt
- 1/2 cup (187.5 g) water, room temperature
Frosting:
- 6 ounces (170.1 g) cream cheese, softened
- 4 tbsp butter, softened
- 2/3 cup (172 g) creamy peanut butter
- 1 cup (182 g) powdered Swerve Sweetener
- 2/3 cup (178.5 g) heavy cream
- 1 tsp vanilla extract
- 1/4 cup (78.86 g) chopped, salted peanuts for sprinkling
Instructions
Cake
- 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.
Frosting
- 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.
Video
Notes
Nutrition
Nutritional Disclaimer
Please note that I am not a medical or nutritional professional. I am simply recounting and sharing my own experiences on this blog. Nothing I express here should be taken as medical advice and you should consult with your doctor before starting any diet or exercise program. I provide nutritional information for my recipes simply as a courtesy to my readers. It is calculated using MacGourmet software and I remove erythritol from the final carb count and net carb count, as it does not affect my own blood glucose levels. I do my best to be as accurate as possible but you should independently calculate nutritional information on your own before relying on them. I expressly disclaim any and all liability of any kind with respect to any act or omission wholly or in part in reliance on anything contained in this website.
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So I made this today, and wasn’t paying attention and, accidently put the whole 2 cups of peanut butter
in the cake mix(had to buy more for the topping). Well, what a great mistake, this cake is absolutely delicious, I can’t wait to share it.
I have been making individual peanut butter mug cakes every night and then I stumbled in your sheet cake. Fabulous! So, so good! I cut the recipe in half and made a 9×13. Perfect for 2 people. I also melted some Lily’s semi sweet chips with a little butter and drizzled the chocolate on top. Hubby said it’s a keeper! Oh, and I didn’t have any protein powder so I decided to just skip that ingredient. The cake came out fine. Thanks so much for sharing!
Will this work with Splenda? There are some sweeteners that I have to stay away from because they trigger migraines so I prefer to stick with what I know I’m okay with. Thanks. I’m soooo looking forward to trying this.
I honestly cannot say as I don’t use Splenda.
You rock my world! I made this yesterday and was in absolute SHOCK about how f***ing good it is.
This is so fabulous! I was able to get the carbs down to 4g net based on my ingredients… what helped most was using Santa Cruz peanut butter (I get it thru Thrive Market), Blue Diamond Almond Flour and Thrive Market Organic coconut flour. SC Peanut Butter has 2g net carbs per 2T, which made the biggest difference. Being single, this allows me to enjoy this lovely treat more often and stay within my macros. Next up, I’ll be trying the chocolate sheet cake with the peanut butter topping and vice versa. SO much flexibility! Thank you so much for all of your hard work on all of your recipes. Haven’t had a bad one yet!!
This is really amazing! My kids can’t stop eating!
Best kind of sheet cake! This is awesome!
Sheet cake is the best!! I love making it for a crowd..it is always gone so fast! Love this peanut butter version! Can’t wait to make it for our next gathering!
This recipe is a DREAM!
This cake is to die for! The frosting is so delicious! Thank you!
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!!!!
Thanks so much!
Sheet cakes are always a hit, but this peanut butter version was so tasty!!!!
My kids really loved this! Such an amazing treat!
Is it still keto if I eat the whole pan?! LOL! So delicious!!
My family is going to love this cake recipe!
Wow Carolyn do you never cease to amaze me with these showstopping recipes! This cake is nothing short of amazing! My whole family loves it & it’s definitely become one of our all time favorite treats that I cannot wait to share with others. So darn delicious! Thank you for all your hard work developing these wonderful treats that make healthier living that much easier:)
So glad to hear it!