Chocolate Mug Cake (Low Carb, High Protein, Sugar-Free)

Name: Chocolate Mug Cake
Prep time: 5 min
Cook time: 1 min
Total time: 6 min
Ingredients: 1 large egg; 1 tbsp avocado oil (or other neutral oil); 1/4 tsp pure vanilla extract; 2 tbsp chocolate protein powder; 2 tbsp granulated sugar-free sweetener; 1 tbsp cocoa powder; 1/4 tsp baking powder; 1 tbsp salted butter (melted); 1 tbsp heavy cream; 1 tbsp chocolate protein powder; 1 tbsp granulated sugar-free sweetener; 1 tsp cocoa powder; 1-2 drops pure vanilla extract

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This chocolate mug cake recipe is a single-serve protein dessert made in the microwave topped with a chocolate frosting. It is gluten-free, sugar-free, low carb, and keto-friendly with 22 grams of protein for the entire recipe, frosting included.

My favorite chocolate mug cake recipe! It's fudgy, rich, and ready in 60 seconds in the microwave, with a thick chocolate frosting on top.

Overhead view of a chocolate mug cake in a black and white ceramic mug, topped with fresh raspberries, on a marble surface with a chocolate bar and bowl of raspberries in the background.

I filmed this chocolate mug cake for a video for Keto Chow in May 2026, for their Mother's Day newsletter. But it wasn't the first time I've made this tasty treat. In 2024, I made this version and in 2022, this one (arguing that mug cakes are the best contribution to the keto community, ha!)

Why are mug cakes the best thing ever? For one, they take minutes to make. And they taste delicious. Plus you can add almost anything extra to make it macro-friendly. I've tested more mug cakes than I can count. (And yes, there have been a lot of fails along the way).

The variations are endless. You can swap flavors, frostings, or fold in chocolate chips. Anything goes once you have the base down. Recipe credit for this one goes to Chef Taffy, and it's my top pick. I hope you enjoy!

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Ingredients
Instructions
Variations
Storage
Top Tip
FAQ
Related
Recipe
Comments

Ingredients

Here's what you'll need to make it:

For the cake:

Egg - Binds the cake and gives it structure. Room temperature mixes in more easily.
Avocado oil - Adds moisture and keeps the cake tender. Any neutral oil works.
Vanilla extract - A small amount goes a long way in a single-serve cake.
Chocolate protein powder - Acts as the flour in this recipe and adds the chocolate base. I used Keto Chow because macro-friendly and makes a nice, thick, fudgy cake.
Granulated sugar-free sweetener - Use your favorite sweetener. I used Swerve.
Cocoa powder - Deepens the chocolate flavor. Grab unsweetened cocoa.
Baking powder - Makes it rise. Don't skip it, or you'll end up with a dense puck.

For the frosting:

Butter - The base of the frosting.
Heavy cream - Smooths the frosting out and makes it spreadable.
Chocolate protein powder - Thickens the frosting without needing powdered sugar.
Granulated sugar-free sweetener - Just a touch more sweetness.
Cocoa powder - A little more chocolate.
Vanilla extract - And a couple of drops to round it out.

See recipe card for quantities.

Instructions

Mix the wet ingredients, stir in the dry, microwave for 60 seconds, and frost. The whole thing comes together in about 6 minutes.

This one is fast. So don't blink.

Before you get started: Grab a large mug, at least 12 ounces, since the cake doubles in height as it cooks. You shouldn't need to grease it, but a swipe of butter inside doesn't hurt for easy release.

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Overhead view of melted butter and beaten egg in a black and white ceramic mug, the first step in making a keto chocolate mug cake

Mix the wet ingredients. Whisk the egg, oil, and vanilla in your large mug until blended.

Dry keto mug cake ingredients - cocoa powder, sweetener, and baking powder - added over melted butter and egg in a black and white ceramic mug, ready to mix

Stir in the dry ingredients. Add the protein powder, sweetener, cocoa powder, and baking powder. Mix until there are zero streaks of egg. Very important! Mix, mix, mix.

Overhead view of unbaked chocolate mug cake batter being stirred with a spoon in a black and white ceramic mug, with a dark chocolate bar and raspberries in the background

Microwave. Cook on full power for 60 seconds. It should rise to about double the height.

Overhead view of a just-microwaved chocolate mug cake in a black and white ceramic mug, showing a domed, fudgy top before toppings are added

Make the frosting. While cake is cooling, whisk frosting ingredients in a small bowl until smooth.

Finally, frost and serve!

Slightly angled overhead view of a chocolate mug cake topped with raspberries in a black and white mug, with a chocolate-coated spoon resting beside it

Sooo fudgy!

Variations

Swap the protein powder flavor. Vanilla, peanut butter, or even strawberry all work as the cake base. Skip or reduce the cocoa powder when you switch flavors so it doesn't overpower.
Add chocolate chips. Fold a tablespoon of chocolate chips into the batter before microwaving for melty pockets throughout the cake.
Make a peanut butter frosting. Swap the cocoa in the frosting for a tablespoon of natural peanut butter.
Top it with whipped cream and berries. A dollop of fresh whipped cream and a few raspberries on top is perfection.

Storage

Mug cake is best fresh out of the microwave. If you somehow end up with leftovers, cover the mug with plastic wrap or transfer the cake to an airtight container and refrigerate for up to 2 days. Pop it back in the microwave for 10 to 15 seconds to soften before eating.

I don't recommend freezing this one. The texture is built around being eaten warm, and freezing dries it out.

Top Tip

Mix batter until you see ZERO streaks. Any streak of unbeaten egg in the batter will scramble in the microwave and give you rubbery bites instead of a fudgy cake. Take a few extra seconds with the whisk or fork on the wet ingredients alone, before adding anything else. Then, mix, mix, mix up the batter. It's the difference between a cake and a chocolate omelet.

FAQ

What kind of protein powder works best for mug cakes?

Milk or whey protein powders work best for this recipe. Keto Chow (milk protein) is what I use, and it bakes into a thick, fudgy texture. Plant proteins tend to come out dry and crumbly in single-serve cakes, so I'd skip them here.

Can I make this chocolate mug cake without protein powder?

Not with this recipe as written. The protein powder does the work of flour and gives the cake its structure. If you want a mug cake without protein powder, you'd need a mug cake recipe built around almond flour or coconut flour instead.

Why did my mug cake come out rubbery?

It's almost always under-mixed egg. Even one small streak of unbeaten egg will scramble in the microwave and create rubbery pockets in the cake. Whisk the wet ingredients until completely uniform before adding any of the dry ingredients.

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