Sometimes you just want cake. Not a whole production, not a full baking session, just a quick single-serving treat you can make in minutes. That’s exactly what this keto funfetti mug cake is all about.
It’s fluffy, sweet, and loaded with colorful sprinkles. Basically everything you loved about funfetti cake as a kid, but without all the sugar and carbs.

The whole thing comes together in one mug with a fork. No mixer, no baking pans, no waiting around for the oven. Just mix, microwave, and top with frosting.
It’s completely low carb and keto friendly, so you can enjoy it without worrying about getting kicked out of ketosis. A real dessert that fits your way of eating.
If you’ve been missing birthday cake vibes on keto, this one is going to make your day.
Why You’ll Love This Recipe
Ready in Under 2 Minutes – This keto funfetti mug cake goes from mixing to done in about 90 seconds in the microwave.

Tastes Like a Birthday Cake – The combo of vanilla extract and almond extract with rainbow sprinkles nails that classic funfetti birthday cake flavor.
Single Serving Saves You From Yourself – You only make one portion so there is no leftover cake sitting on the counter tempting you all night.
Recipe Ingredients
- 3 tbsp Almond Flour
- 1 tbsp Coconut Flour
- 2 tbsp Granulated Erythritol
- 1/2 tsp Baking Powder
- 1 large Egg
- 2 tbsp Heavy Whipping Cream
- 1 tbsp Melted Butter
- 1/2 tsp Vanilla Extract
- 1/4 tsp Almond Extract
- 1 tbsp Sugar-Free Rainbow Sprinkles
- 2 tbsp Sugar-Free Vanilla Frosting (store-bought or homemade)
- Extra Sprinkles for topping
How To Make
Step 1
In a large microwave-safe mug, whisk together the almond flour, coconut flour, granulated erythritol, and baking powder until no lumps remain.
Step 2
Add the egg, heavy cream, melted butter, vanilla extract, and almond extract. Whisk vigorously with a fork until the batter is completely smooth.
Step 3
Gently fold in the sugar-free rainbow sprinkles with a spoon, being careful not to overmix so the colors don’t bleed.
Step 4
Microwave on high for 70 to 80 seconds. The cake should be risen and set on top with a slightly moist center. If still wet, microwave in 10-second bursts.
Step 5
Let the mug cake cool for 1 to 2 minutes. Top with sugar-free vanilla frosting and a scattering of extra sprinkles. Eat straight from the mug with a spoon.

Tips
Use a Big Enough Mug
This cake rises a lot more than you’d expect. Use a mug that holds at least 12 ounces, even though the batter doesn’t look like much at the start.
If your mug is too small, the batter will overflow in the microwave and you’ll end up with a mess instead of a cake. A wider mug also cooks more evenly than a tall, narrow one.
Whisk the Dry Ingredients First
Coconut flour clumps really easily, and if those clumps are still hiding in the batter when you microwave it, you’ll bite into dry, chalky spots in the finished cake.

Take a few extra seconds to really break up the dry ingredients with a fork before adding anything wet. Get into the corners of the mug too since flour loves to hide there.
Don’t Skip the Almond Extract
The almond extract is what makes this taste like a real funfetti cake and not just a plain mug cake with sprinkles on top. It adds that classic bakery flavor that vanilla alone can’t pull off.
Just make sure you stick to 1/4 teaspoon. Almond extract is super strong, and even a tiny bit extra can make the whole thing taste bitter and overpowering.
More Recipes
- Keto 90-Second Chocolate Mug Cake
- Low Carb Red Velvet Mug Cake
- Keto Vanilla Cupcakes with Buttercream
- Keto Boston Cream Pie Cupcakes
- Keto Sugar Cookies with Vanilla Frosting
Frequently Asked Questions
Can I bake this in the oven instead of the microwave?
Yes, you can. Pour the batter into a small oven-safe ramekin and bake at 350°F for about 15 to 18 minutes, or until a toothpick comes out mostly clean with just a few moist crumbs.
The texture will actually be a bit more like a traditional cake in the oven compared to the microwave version, so it’s worth trying if you have the extra time.
Keto Funfetti Mug Cake
Ingredients
Method
- In a large microwave-safe mug, whisk together the almond flour, coconut flour, granulated erythritol, and baking powder until no lumps remain.
- Add the egg, heavy cream, melted butter, vanilla extract, and almond extract. Whisk vigorously with a fork until the batter is completely smooth.
- Gently fold in the sugar-free rainbow sprinkles with a spoon, being careful not to overmix so the colors don't bleed.
- Microwave on high for 70 to 80 seconds. The cake should be risen and set on top with a slightly moist center. If still wet, microwave in 10-second bursts.
- Let the mug cake cool for 1 to 2 minutes. Top with sugar-free vanilla frosting and a scattering of extra sprinkles. Eat straight from the mug with a spoon.