This keto coffee cake mug cake is everything you want in a quick dessert – warm, soft cake with a buttery cinnamon streusel on top. And it’s ready in about two minutes.
Coffee cake is one of those treats that feels impossible to make low carb. The crumbly topping, the moist cake, that cinnamon sweetness – it all usually depends on sugar and regular flour.
But this version uses almond flour, coconut flour, and a sugar substitute to keep the carbs low while still tasting like the real thing. It’s completely keto friendly.
The secret to getting that perfect moist texture is sour cream in the batter. It makes the cake soft and tender without adding a bunch of extra carbs.
And the streusel topping with pecans gives you that classic buttery crunch you expect from a good coffee cake. It all comes together in a single mug.
Why You’ll Love This Recipe
That Buttery Streusel Crunch Is Unreal – The pecan streusel topping crisps up as it cools and gives you that classic coffee cake crumble you thought you had to give up on keto.
Perfectly Moist and Tender – The sour cream in the batter keeps this mug cake soft and rich instead of dry and rubbery like so many microwave cakes.
Tastes Like Real Coffee Cake – The cinnamon and brown sugar substitute combo nails that warm bakery flavor you crave without all the carbs.
Recipe Ingredients
For the Streusel Topping
- 1 tbsp Almond Flour
- 1 tbsp Cold Butter, cut into small pieces
- 1 tbsp Golden Brown Sugar Substitute
- 1/4 tsp Ground Cinnamon
- 1 tbsp Chopped Pecans
For the Cake
- 3 tbsp Almond Flour
- 1 tbsp Coconut Flour
- 2 tbsp Granulated Erythritol
- 1/2 tsp Baking Powder
- 1/4 tsp Ground Cinnamon
- 1 Large Egg
- 2 tbsp Melted Butter
- 2 tbsp Sour Cream
- 1/2 tsp Vanilla Extract
- Pinch of Salt
How To Make
Step 1
Make the streusel first. In a small bowl, combine the almond flour, brown sugar substitute, and cinnamon. Add the cold butter pieces and pinch everything together with your fingers until you get coarse, crumbly pieces. Mix in the chopped pecans and set aside.
Step 2
In a microwave-safe mug (at least 12 oz), whisk together the almond flour, coconut flour, granulated erythritol, baking powder, cinnamon, and salt.
Step 3
Add the egg, melted butter, sour cream, and vanilla extract. The sour cream is the secret here as it makes the cake incredibly moist and tender. Stir until the batter is smooth and creamy.
Step 4
Scatter the streusel topping evenly over the batter. Do not press it in or stir it. You want it sitting right on top so it stays crumbly.
Step 5
Microwave on high for 70 to 80 seconds, until the cake beneath the streusel is set and springs back when lightly touched. The streusel on top should look golden and slightly toasted.
Step 6
Let the mug cake rest for 1 minute before eating. The streusel will crisp up slightly as it cools, giving you that perfect buttery crunch on top of the soft, moist cake.
Tips
Use a Big Enough Mug
This batter rises a lot in the microwave, so use a mug that holds at least 12 oz. A standard coffee mug is usually around 10 oz, which is too small and the batter will overflow and make a mess.
A wide-mouth mug works even better than a tall narrow one. More surface area means more room for the streusel topping and more even cooking throughout the cake.
Keep the Butter Cold for the Streusel
The butter for the streusel needs to be cold, straight from the fridge. If the butter is soft or room temperature, it will just melt into the flour and you’ll end up with a paste instead of crumbly pieces.
Cut it into small cubes and then pinch it into the dry ingredients quickly with your fingertips. You want visible little chunks of butter mixed in because those are what melt in the microwave and create that crumbly, buttery topping.
If your kitchen is warm and the butter softens while you’re working, pop the streusel in the freezer for a couple minutes before you put it on the batter.
Don’t Skip the Sour Cream
The sour cream is what keeps this mug cake from turning out dry and rubbery, which is a common problem with keto baked goods since almond and coconut flour absorb a lot of moisture.
Use full-fat sour cream, not light or fat-free. The fat content is what gives the cake that soft, tender crumb. If you don’t have sour cream, full-fat Greek yogurt works as a swap, but sour cream gives a better texture here.
More Recipes
- Keto 90-Second Chocolate Mug Cake
- Keto Funfetti Mug Cake
- Keto Cinnamon Swirl Coffee Cake
- Low Carb Red Velvet Mug Cake
- Keto Apple Cinnamon Crisp
Frequently Asked Questions
Can I make this in the oven instead of the microwave?
Yes, you can bake it in a small oven-safe ramekin at 350°F for about 15 to 18 minutes, or until a toothpick comes out clean. The oven method actually gives the streusel an even better golden crunch on top.
Just keep an eye on it since oven temperatures vary, and you don’t want to overbake it or the cake will dry out.
Keto Coffee Cake Mug Cake
Ingredients
Method
- Make the streusel first. In a small bowl, combine the almond flour, brown sugar substitute, and cinnamon. Add the cold butter pieces and pinch everything together with your fingers until you get coarse, crumbly pieces. Mix in the chopped pecans and set aside.
- In a microwave-safe mug (at least 12 oz), whisk together the almond flour, coconut flour, granulated erythritol, baking powder, cinnamon, and salt.
- Add the egg, melted butter, sour cream, and vanilla extract. The sour cream is the secret here as it makes the cake incredibly moist and tender. Stir until the batter is smooth and creamy.
- Scatter the streusel topping evenly over the batter. Do not press it in or stir it. You want it sitting right on top so it stays crumbly.
- Microwave on high for 70 to 80 seconds, until the cake beneath the streusel is set and springs back when lightly touched. The streusel on top should look golden and slightly toasted.
- Let the mug cake rest for 1 minute before eating. The streusel will crisp up slightly as it cools, giving you that perfect buttery crunch on top of the soft, moist cake.