Peanut Butter & Chocolate Protein Cupcakes

You’ll love these rich, protein packed, ONE BOWL keto & gluten-free chocolate cupcakes! The peanut butter and whey protein frosting is deliciously chewy like caramel toffee. And the best part: they have only 1.5 net carbs a pop!

Low-carb chocolate cupcake with peanut butter whey protein frosting.
These keto cupcakes are protein balls in disguise!

The best high protein keto cupcakes

Cupcakes are beautiful, but recipes are often complicated, needing lots of equipment and time. But these are different: They are the easiest and fastest cupcakes ever, keto or not! Made in one bowl only, mixed up in a matter of minutes, just by hand – and that includes the frosting!

These keto peanut butter and chocolate cupcakes are super satiating, will remain fresh and delicious for a few days if kept air tight, and don’t need to be refrigerated. They’re like a cupcake version of lembas!

One bowl to rule them all.

The peanut butter caramel frosting is soft and chewy on the inside, and the outside sets harder, creating a toffee candy sort of texture that is to die for! And it’s the easiest frosting to make ever – just one bowl, one spoon. Mix the the 4 ingredients by hand. No creaming butter and sugar for half an hour. No pile of dishes to do. Actually, if after mixing the cupcake batter you wash the bowl, you can just use it again for the frosting: 1 bowl for the whole cupcake recipe.

They journey well too. Generally cupcakes are pretty fragile beings, that need gentle care. To be carried around they need to be put in special travel boxes, and you can still ruin their ephemeral beauty by simply letting they touch each other or the sides of the box. But these keto cupcakes? You can just throw them in a zip bag and I promise you, they will arrive unscathed anywhere you take them. The frosting does not move!

I flew with some hurriedly thrown in the front pocket of my cabin bag, where they remained forgotten until near landing. After a hard day of work, when I found myself in desperate need of a moment of joy, I looked for my precious keto cupcakes. I opened the bag expecting to see them sadly smashed, but they looked as perfect as they did in the morning.

Cupcake ingredient notes

Keto flours: As far as keto, low-carb and gluten-free cupcake recipes go, these are pretty unique: there’s no almond flour or coconut flour in them.

Instead, a combination of flax meal, lupin flour and unflavored whey protein, which is keto approved, gluten-free and super high protein! Cupcakes for the gains, yeah!

The flavors: The super rich, decadent chocolate experience comes from a mix of the best sugar-free cocoa with a tiny bit of espresso powder. Don’t worry, you won’t feel the coffee taste. Espresso powder, used in the right quantity, just intensifies the chocolate flavor. There’s some vanilla too, to round and smooth things up.

How to make

Warm the butter on a double boiler or microwave until completely melted. Do not boil the butter. If using the microwave, do it in short bursts or set it to defrost, which will gently warm up without burning.

Add the heavy cream to the butter, and mix them together. Then, add the sugar-free cocoa powder, coffee or espresso powder, vanilla, and salt. Mix it vigorously with a spatula (I broke the whisk on the first picture doing this) and it will become a very thick dough (1).

Add the eggs, one by one, breaking the yolks and incorporating them into the batter. It’s gonna be smelling divine by now, and looking almost like melted chocolate (2). Don’t eat it yet!

Step by step for the low-carb chocolate cupcakes batter.

Add powdered sweetener (I used erythritol stevia blend), mix, and sieve in the flours (3) – unflavored whey protein, lupin flour and flax meal, plus the xanthan gum and baking powder. Mix the flours in until everything comes together without colored streaks.

The batter will seem quite stiff. Add the warm water, slowly, while mixing. The final consistency should look as in picture 4. Wait for a couple of minutes, for the flax meal and xanthan to absorb the liquid and settle, and give it a last stir before filling in the liners.

There should be enough for 12 cupcakes liners- I recommend silicone, as whey has a way (sorry, I couldn’t resist) of sticking to paper. You can also butter a muffin tray and pour the batter directly into the holes.

Put the cupcakes into the preheated oven at 170 °C (338 °F) for 25 minutes, or until a toothpick comes out mostly clean.

Frosting ingredients

For this super easy sugar-free keto frosting, you’ll need only 4 ingredients: peanut butter, unflavored whey protein, liquid sweetener (I like stevia) and water!

For this frosting to be pipeable, the peanut butter should be smooth – you don’t want the peanut pieces clogging the icing nozzle. If all you have is crunchy peanut butter, you can make it work: for a more rustic look, you can decorate the cupcakes by just leveling the frosting on top of them with a small spatula or a butter knife.

Halved high protein chocolate cupcake with peanut butter careamel frosting.

What’s non-negotiable: natural peanut butter, made with peanuts only – maybe some salt. The consistency will not be right with other types. All natural peanut butter generally shows a layer of peanut oil on top, because it hasn’t been adulterated with palm or hydrogenated oils to keep it from separating.

Lazy people prefer to buy peanut butter with bad stuff added, but not you. You just stir your 100% peanuts peanut butter before using it and the problem is solved.

How to make peanut butter whey frosting

Add the whey protein and 1/2 of the water to a medium bowl. Start hydrating the protein, working with a spoon to form a thick paste. The liquid has to be added little by little to prevent the whey protein powder from clumping up. When the paste is smooth, add the rest of the water.

Add the peanut butter and sweetener (I used liquid stevia). You can also add vanilla for more flavor. Mix it vigorously, it’s a very sticky toffee like paste. Try the keto frosting for sweetness before frosting the cupcakes, and adjust the sweetener to your liking.

Step by step pictures for the peanut butter and whey protein keto cupcake frosting.

Although the ratios I give you for this keto frosting recipe work well with my ingredients, your brand of whey protein might be more drying, and your peanut butter more or less oily. Start with my suggested measures, and adjust accordingly.

Tips for the best frosting

The ideal texture for this keto frosting is somewhere between a stiff toffee consistency that’s too hard to pipe and will burst your piping bag – been there 😒 – and a caramel that’s too soft and will not hold its shape on top of the cake – been there too 😪

Both problems are easy to fix: If the caramel is too soft, add a little more whey protein – no more than 10 grams or a heaping teaspoon at a time. If it’s too hard, add a tiny bit more liquid, water or milk. Stir very well after each addition, to check if you reached the best piping consistency.

Low-carb chocolate cupcake with peanut butter whey protein frosting.

Chocolate Peanut Butter Protein Cupcakes

5 from 15 votes
Rich, protein packed chocolate cupcakes with peanut butter and whey protein frosting, made in ONE BOWL! Gluten-free & keto, only 1.5 net carbs a pop.
Author: Pris Frank
Prep Time 25 minutes
Cook Time 25 minutes
Total Time 50 minutes
Course Dessert
Cuisine American, Low-carb
Servings 12 cupcakes


For the chocolate cupcakes

For the peanut butter frosting


Chocolate cupcakes

  • In a large bowl, melt butter and stir in the heavy whipping cream.
  • Add the cocoa powder, coffee or espresso powder, vanilla and sweetener. Whisk until smooth.
  • Add the eggs, one by one, mixing very well between each.
  • Sieve in the flours: lupin, whey protein and flax meal, plus the baking powder, baking soda and xanthan gum. Mix until the flours are well incorporated.
  • Add warm water, slowly, while whisking. Let the batter sit for a couple of minutes, and give it a last mix before filling the liners.
  • Pour the batter into 12 silicone cupcake liners or directly into the buttered holes of a muffin pan.
  • Take the tray into a preheated oven at 170 °C (340 °F) for 25 minutes, or until a toothpick comes out mostly clean.

Peanut butter protein frosting

  • Add water to whey, little by little, and mix until creamy and completely lump free
  • Add peanut butter and sweetener drops, and vanilla if using it
  • Mix vigorously until it has a hard caramel/soft toffee like consistency. Try it and adjust sweetener if necessary.
  • If it's too hard to pipe, add more water. If it's too soft to pipe, add more whey


I add stevia (or monk fruit) powder to my erythritol to make it 100% as sweet as sugar. This way, I can use less erythritol, avoiding the cooling taste that shows up when it's used in excess, while also masking the bitter aftertaste of stevia and bulking it up. There are many brands that sell this sweetener concoction prepacked, either as erythritol plus stevia, or erythritol plus monk fruit, or erythritol plus both stevia and monk fruit. I just find it cheaper to make my own 😉


Serving: 1Calories: 243kcalCarbohydrates: 6.6gProtein: 17.7gFat: 16.2gFiber: 5.1gSugar: 7gNet Carbohydrates: 1.5g
Tried this recipe?Leave a comment and let us know how it was!

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  1. These keto cupcakes looks so awesome! I really appreciate all of the tips you give for making sure they turn out perfectly!

  2. These cupcakes were absolutely delicious with the best flavor and texture! Love that they have added protein too! Will definitely be making again and again!

  3. These cupcakes were sooo good! And I love that they are gluten free and full of protein. Thanks for an amazing recipe!

  4. These keto cupcakes look so delicious and scrumptious! My family is going to love this! Can’t wait to give these a try!

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