Peanut Butter Keto Mug Cake

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This peanut butter keto mug cake takes only minutes to make! It’s tender and lightly sweetened, and makes a wonderful easy breakfast or dessert.

A keto mug cake in a white mug with chocolate chips strewn around and a spoonful taken out of it.

Sometimes I create recipes with a specific outcome in mind. And sometimes I throw together some ingredients on a whim and hope for the best. This keto mug cake recipe falls into the latter category!

But while it was rather slapdash in its creation, it quickly became a fan favorite recipe. And a family favorite too! I often whip these little keto cakes up when we need a quick treat.

You know that I take peanut butter and chocolate very seriously. And many of my recipes are quick and easy, like Keto Peanut Butter Bars and easy Peanut Butter Protein Balls. So you can rest assured that these easy mug cakes are good stuff!

A peanut butter keto mug cake in a white porcelain coffee cup on a white saucer.

Why you will love this recipe

Mug cakes have appeal because they are so easy to make. But they can also have a bit of an odd texture from the fast cooking method. They tend to end up a bit spongy.

These keto peanut butter mug cakes differ in that regard. There is something about the addition of peanut butter that gives them a proper cake texture. And yet they take only about 5 minutes to make.

They really are super family friendly and since this recipe makes six, you can feed the littles and yourself. You can also scale the recipe back and make only three servings, which is more appropriate for those who live alone or are doing keto alone.

And these easy cakes store quite nicely. I do recommend cooking them all at once, as the batter thickens if it sits too long. But you can store the finished keto mug cakes in fridge and re-warm them easily when you want another serving.

Reader Reviews

“These are the Creme de la Creme of mug cakes….my all time favorite (and I am beginning to be way too familiar with mug cakes). But the peanut butter adds some density so that these are not just fluff on a spoon. There is just the right amount of substance….and the flavor is FABULOUS. Caroline, you are amazing. You obviously put a lot of testing into your recipes because they are the gold standard in my opinion. thank you for putting food worth eating on our low carb table.” — Deborah

“I was skeptical to try this because I am in South Africa and we have limited choice of ingredients. Well, they cam out perfectly and I am so happy I made the effort, thank you! It was so easy to make and I will definitely make it again!”– Linda

“Wow! Easy and delicious ! I’m addicted! I don’t usually like the texture of mug cakes, but these are wonderful. Thanks again for another winner!”– Joan

Ingredients needed

Peanut butter: I recommend a good natural peanut butter like Santa Cruz. But you can use any nut butter here if you are allergic to peanuts.
Butter: I like to use salted butter because the salt brings out a little flavor. You can also use coconut oil if you want to be dairy-free.
Almond flour: As always, the finer your almond flour, the better the texture of your cakes. I have been using Blue Diamond lately and find it works quite well.
Sweetener: Use your favorite granular sweetener. I really like the flavor that Swerve Brown adds here, but you can also use allulose or BochaSweet.
Dark chocolate chips: Both ChocZero or Lily’s work nicely in this mug cake recipe. You can also skip the chips to save on a few carbs, if you like.
Kitchen staples: Eggs, baking powder, and vanilla extract.

Step-by-step directions

A collage of four images showing how to make keto peanut butter mug cakes.

1. In a microwave safe bowl, melt the peanut butter and butter together in short bursts, stirring until smooth.

2. In a medium bowl, whisk together the almond flour, sweetener, and baking powder.

3. Stir in the eggs, vanilla extract, peanut butter mixture, and water until well combined. Stir in the chocolate chips.

4. Divide among 6 ramekins or mugs and microwave each for about 1 minute, until puffed and set. Serve warm.

Close up shot of peanut butter keto mug cake in the mug with chocolate chips on top.

Expert tips

Peanut butter tends to thicken cake batters the longer it sits, so you need to work relatively quickly on this one. Try to get it into the mugs as soon as it’s all mixed together and then cook them straight away.

Several readers have asked if they can prepare the batter and then refrigerate the cakes until they are ready to make them. This doesn’t work well because the batter can thicken and the cakes won’t rise properly. You are better off cooking all of the cakes and then re-warming it when you are ready to eat.

We like to eat them right out of the mugs but if you want to remove them, be sure to grease your mugs or ramekins very well.

Oven Baked Method: If you prefer to make these in your oven, try baking them at 350ºF for 12 to 15 minutes.

Nut-Free Version: You can make these with sunflower butter and sunflower seed flour. But you will want to replace 1 tablespoon of the water with some lemon juice to offset the green reaction that occurs between sunflower seeds and baking powder.

Close up shot of a spoonful of keto mug cake in a white mug.

Frequently Asked Questions

How do I store keto mug cakes?

Cover extra mug cakes tightly and store at room temperature for 1 day. You can also store them in the refrigerator for up to 5 days. To reheat, place it in the microwave for 15-20 seconds until just warm.

Can I freeze keto mug cakes?

You can also freeze extra mug cakes. Wrap them tightly in plastic wrap or foil and freeze for 3-6 months. If freezing, it is best to remove them from the mug first, then wrap and freeze.

How many carbs are in a peanut butter keto mug cake?

This keto mug cake recipe has 6.7g of carbs and 3g of fiber per serving. That comes to 3.7g net carbs per mug cake.

Peanut Butter mug cake in a white mug with whipped cream and chocolate chips on top and a spoon sticking out of it.

More keto mug cake recipes

Keto Mug Brownie Recipe

This keto brownie in a mug is gooey and decadent, and serves just one person. It’s the perfect single-serve dessert when you need chocolatey goodness but you don’t want the leftovers.

Get the recipe

Close up shot of a keto mug brownie with a spoon digging into it.

Keto Mug Cake Recipe

Keto mug cakes are perfect when you need a delicious dessert in a flash. There’s nothing easier or more comforting than this easy sugar-free snickerdoodle mug cake. Only 7 minutes, start to finish!

Check out this recipe

Close up shot of keto mug cake with a spoon stuck into it.

Protein Mug Cake Recipe

This Chocolate Protein Mug Cake tastes like an indulgent dessert and takes only 2 minutes to whip up. With 15g of protein per serving, it’s a sugar-free treat you can feel good about.

Get the recipe