This keto chocolate mug cake is rich, chocolatey, gooey, and ready in five minutes.
It's one of the best solutions I have found when craving something sweet and chocolatey. I love the built-in portion control!
I've been working on this recipe for six months now. I wanted it to be just right, with a deep chocolate flavor and tender crumb. Just as important, I wanted it to be easy!
I finally achieved perfection when I decided to use nut butter instead of flour as the base for the cake. The result is heavenly: rich, tender, and moist. Plus, it's ready in just five minutes (including mixing the ingredients). It's one of my favorite keto desserts!
Jump to:
Ingredients
You'll only need a few simple ingredients to make this cake. The exact measurements are included in the recipe card below. Here's an overview of what you'll need:
- Almond or peanut butter: I usually use natural almond butter. The only ingredient is almonds, and you need to mix it and then refrigerate it to prevent oil separation. Sometimes, I use natural creamy peanut butter.
- Egg: I use large eggs in most of my recipes, including this one.
- Sweetener: I use stevia glycerite. You can use 2 tablespoons of a granulated sweetener instead.
- Salt: Just a little bit to enhance the chocolate flavor. If your nut butter contains salt, you should omit the salt.
- Unsweetened cocoa powder: It's best to use Dutch-processed cocoa powder. It's milder and less acidic than natural cocoa powder.
- Baking powder: Make sure it's fresh. And if needed, also make sure it's gluten-free.
Variations
- You can experiment with different kinds of nut butters, as long as they are creamy and unsalted.
- You can use 2 tablespoons of granulated sweetener instead of stevia.
- Try adding 2 tablespoons of dark chocolate chips for an extra indulgent cake! This is my husband's favorite version.
Instructions
Scroll down to the recipe card for detailed instructions. Here are the basic steps for making this recipe:
Whisk the ingredients together in a 12-ounce mug, in the order listed. I usually start with the liquid ingredients, then add the dry ones. The baking powder is added last, to make sure it doesn't lose its potency.
Microwave the cake until it's puffy and cooked through but still moist. The top should still be very gooey, but not completely liquid. In my microwave oven, on 100% power, it takes 40 seconds.
Expert Tips
- One of the best things about this cake is that you can make it the night before, cover and refrigerate it, then quickly microwave it in the morning.
- As you know, microwave ovens vary, so it's difficult to say with certainty how long you should microwave the cake. I recommend starting with 30 seconds and then checking it and adding 10 more seconds if needed.
Recipe FAQs
I usually make this cake with creamy almond butter. But I've tried creamy unsalted peanut butter, and that worked too. If you use salted peanut butter, you should omit the salt.
If you try different types of nut butter, you might need to adjust the liquids, depending on their thickness. I once made this cake with tahini (sesame butter) which was very thick. So I had to add a tablespoon of water to the batter.
You'll know it's too thick if it's difficult to stir. The batter should be thick but smooth, velvety, and easy to stir.
Although natural cocoa powder will work in this recipe, it won't be as tasty. Dutched cocoa powder is darker, milder, and less acidic. It creates a better, smoother chocolate experience.
As with all microwave cakes, you will need to experiment to find exactly how long you should microwave the cake in your microwave and when using your mug.
I use a 12-ounce mug in this recipe. Try to stick with a similar size mug. Using a much larger mug (such as a 16-ounce mug) could dry out the cake. A smaller mug could result in the cake spilling out of it while in the microwave.
As for how long to microwave this cake, I would start with 30 seconds, then check to see how it looks. Your goal is to keep it soft and gooey, but not liquid.
It's definitely better to err on the side of microwaving too little than too much. You can always keep microwaving in 10-second increments, but you can't un-microwave a dry cake!
Yes! It amazes me each time. Look at the photo below - you can see that this mug cake has a real cake crumb, light and fluffy. It's magnificent! 
Serving Suggestions
This cake is excellent as it is, and that's how I usually enjoy it. It's so moist and chocolaty! A truly wonderful treat. But if you'd like to add something, here are a few ideas:
- Top it with keto whipped cream or with keto chocolate whipped cream.
- Dust it with a powdered sweetener.
- After the initial 30 seconds in the microwave, scatter a few chocolate chips on top and then microwave for the additional 10 seconds.
- Top it with a keto cream cheese frosting or with the peanut butter frosting I use in these keto chocolate cupcakes.
- This is the perfect summer dessert because you don't need to heat the oven. In the summer, I serve this cake with a tall glass of chilled almond milk, iced coffee, or iced tea. In the winter, it's great with coffee or mint tea.
Storing Leftovers
The entire idea behind a mug cake is a single serving and no leftovers (unlike this almond flour chocolate cake, for example).
But if you have leftovers, you can keep them in the fridge, in an airtight container, for up to 4 days. Reheat them in the microwave at 50% power.
More Mug Cake Recipes
Foodie Newsletter
I send out a weekly newsletter with a recipe and tips. Want these recipes in your inbox? Subscribe today! You can unsubscribe at any time.
Recipe Card
Keto Chocolate Mug Cake
Ingredients
- 2 tablespoons almond butter - creamy, natural, or peanut butter (32 grams)
- 1 large egg
- ½ teaspoon stevia glycerite - (scant; equals about 2 tablespoons of sugar)
- Dash salt - (omit if your nut butter is salted)
- 1 tablespoon unsweetened cocoa powder
- ½ teaspoon baking powder - gluten-free if needed
Instructions
- In a 12-ounce microwave-safe mug, using a small hand whisk or a fork, mix the almond butter and egg until smooth. This will take some time - about 2 minutes until completely smooth - so try to be patient.
- Add the sweetener and salt (if using), whisking to incorporate.
- Whisk in the cocoa powder, then add the baking powder. Mix well, making sure there's no nut butter residue in the bottom of the mug. The batter should be smooth and uniform.
- At this point, the batter should fill the mug about halfway to the top. The cake will rise dramatically as it cooks, so the mug you use needs to accommodate that.
- Place the mug in the microwave. Microwave it, uncovered, for 30 seconds. Check to see if the cake is still very liquid on top - if so, microwave it for 10 more seconds. It should still be very gooey and soft on top when you remove it from the microwave, but not completely liquid. Resist the temptation to microwave more (unless the batter is still completely liquid) - a chocolate cake is always better gooey than dry.
- Remove the mug from the microwave and allow the cake a few seconds to settle before digging in.
Video
Notes
Nutrition per Serving
Disclaimers
Cup measurements refer to the standard American cup, which is 240 milliliters. Most of my recipes are low-carb (or keto) and gluten-free, but some are not. Please verify that a recipe fits your needs before using it. Recommended and linked products are not guaranteed to be gluten-free. Nutrition info is approximate, and the carb count excludes non-nutritive sweeteners. Nutrition info may contain errors, so please verify it independently. Recipes may contain errors, so please use your common sense when following them. Please read these Terms of Use carefully before using any of my recipes.
Vered DeLeeuw, LL.M., CNC, has been following a low-carb real-food diet and blogging about it since 2011. She's a Certified Nutrition Coach (NASM-CNC), has taken courses at the Harvard School of Public Health, and has earned a Nutrition and Healthy Living Certificate from Cornell University. Her work has appeared in several major media outlets, including Healthline, HuffPost, Today, Women's Health, Shape, and Country Living. 
jenna
How long and at what temperature would you bake this? I don't like to use the microwave.
Vered DeLeeuw
I recommend baking it in a 350°F oven for 12 minutes, then checking to see if it needs more time in the oven. Make sure to use an oven-safe ramekin.