Looking for something sweet and healthy? Look no further than this oat flour mug cake! This personal-sized cake is light and fluffy and made with wholesome ingredients. Go ahead and indulge your sweet tooth!

I love mug cake! It's such a quick and easy dessert. And I've tried so many different recipes, but this oat flour cake is my favorite.
It cooks up light and fluffy- you won't believe it's made in a microwave. Plus, the ingredients are easy to find and good for you. Here's what you'll need:
Ingredients:
To make this oat flour mug cake, you'll need the following ingredients:
Ingredient notes:
- Oat Flour– Oat flour is sold in stores, but it’s also super easy to make at home. Simply blend old-fashioned oats in a high-speed blender until the oats become a fine powder (about 30 seconds to a minute). Store your oat flour in an air-tight container for up to three months.
- Coconut Sugar- Feel free to substitute regular brown sugar instead of coconut sugar.
- Grass-Fed Butter- I use grass-fed butter for the health benefits but feel free to use regular butter. Or you can substitute olive or canola oil.
- Sparkling Water- I tested the mug cake using sparkling water and regular water, and I found that using sparkling water created a lighter, fluffier cake. But feel free to use regular water if that's what you have.
Instructions
Oat flour mug cake is super easy to make. Follow these instructions:
- Mix the oat flour, cornstarch, coconut sugar, baking powder, and salt in a small microwave-safe mug or ramekin.
- Add in the melted butter, vanilla extract, and water. Mix together with a spoon until everything is well incorporated.
- Microwave on high for 50-60 seconds. Mine is perfect at 55 seconds.
- Allow to cool and top it with your favorite toppings, such as whipped cream or nut butter.
FAQs
Yes! Oat flour is simple to make at home. Simply blend old-fashioned oats in a high-speed blender until the oats become a fine powder (about 30 seconds to a minute). Store your oat flour in an air-tight container for up to three months.
Yes! You can customize your mug cake with various nuts and chocolate chips. Add them to the batter before microwaving, or use them as toppings.
Want more mug cake recipes?
Check these out!
Powdered Peanut Butter Mug Cake (4 Ingredients)
Double Chocolate Protein Mug Cake (made with oats)
As always, please let me know how you like the oat flour mug cake in the comments. Your feedback means a lot to me, and your star ratings encourage other readers to give this recipe a try.
Enjoy!
Crystal
📖 Recipe
Oat Flour Mug Cake
Ingredients
- ⅓ cup oat flour*
- 1 tablespoon cornstarch
- 1 and ½ tablespoons coconut sugar or brown sugar
- ¼ teaspoon baking powder
- pinch salt
- 1 tablespoon grass-fed butter melted, or olive or canola oil
- ¼ teaspoon vanilla extract
- 2 tablespoons sparkling water* or regular tap water, see notes
Instructions
- Mix the oat flour, cornstarch, coconut sugar, baking powder, and salt in a small microwave-safe mug or ramekin.
- Add in the melted butter, vanilla extract, and water. Mix together with a spoon until everything is well incorporated.
- Microwave on high for 50-60 seconds. Mine is perfect at 55 seconds.
- Allow to cool and top it with your favorite toppings, such as whipped cream or nut butter.
- Enjoy!
Notes
- Oat Flour– Oat flour is sold in stores, but it’s also super easy to make at home. Simply blend old-fashioned oats in a high-speed blender until the oats become a fine powder (about 30 seconds to a minute). Store your oat flour in an air-tight container for up to three months.
- Sparkling Water- I tested the mug cake using sparkling water and regular water, and I found that using sparkling water created a lighter, fluffier cake. But feel free to use regular water if that's what you have.
Jess says
So delicious and easy to make
Gina Abernathy says
I love mug cakes. They are the perfect size for dessert and for those nights or afternoons I just need a little something special.
Nancy says
I really need to try this mug cake trend. Yours looks fantastic
C. K. says
I love mug cakes, and this recipe looks great. However, I really can't rate the recipe because I had to substitute for the cornstarch. I am allergic to corn. I tried tapioca starch, but that really didn't work. Any suggestions?
Crystal Yentzen says
You can try substituting arrowroot powder. Let me know if you try it!
Crystal
Val says
Thanks for having the nutritional info.
Hope to try this recipe soon.
Crystal Yentzen says
You're welcome! Please let me know how they turn out.
N.K says
Beautiful recipe. I skipped the vanilla extract and put in some ginger powder instead. My oat flour is a bit more coarse so I could have done with a tbsp extra of liquid. I used milk instead of water though. Feels more hearty.
Thanks so much and very likely to do this again! 🙂
Crystal Yentzen says
Thanks so much for the lovely comment. I'm so happy you like the mug cake!