Oat flour mug cakes are the perfect single serve dessert ready in just minutes. This oat mug cake is easy to make with simple, pantry ingredients and is soft, fluffy and perfectly sweetened. Enjoy this healthy oat mug cake anytime you want something sweet.

Why you will love this recipe

• So easy to make – making oat flour mug cakes could not be easier. Simply measure out the ingredients, stir and microwave. The hardest part is letting it cool for a few minutes before enjoying!
• Simple ingredients – this oat mug cake uses easy to find ingredients you likely already have in your pantry, making this perfect for anytime you are wanting something sweet to enjoy. This recipe is made without eggs, gluten or dairy and can easily be made nut free.
• Single serve portions – for those times when you don’t want to turn on the oven or make a big batch of cookies or cake, mug cakes made with oat flour are the perfect solution.
• Versatile – change up the flavors with different mix in ingredients and toppings. You could make this vegan oat flour mug cake everyday and never repeat a flavor.

Ingredients

• Avocado oil or olive oil – avocado oil is a great neutral oil that won’t add any flavor to the mug cake. You can also use olive oil but it may add a little olive oil flavor. Some other options are melted coconut oil or melted butter or ghee.  
• Coconut sugar – Coconut sugar is used to sweeten the oat flour mug cake. You can also use regular sugar or brown sugar in place of the coconut sugar.
• Vanilla extract (optional) – vanilla really helps to make this taste like a decadent dessert. If you don’t have vanilla extract, simply omit it, it will still be delicious.
• Oat flour – oat flour creates a super soft, fluffy mug cake. Oat flour is made from grinding up oats into a fine powder. If you need this to be gluten free, be sure to use a gluten free oat flour (oats are naturally gluten free but can get contaminated while processing). Check out my tips below if you only have rolled oats or quick cooking oats.
• Dairy free milk – use whatever your favorite dairy free milk is for this recipe. You can use almond milk, oat milk, cashew milk, coconut milk (in the carton), flax milk, hemp milk, etc. You could even use regular dairy if you are not dairy free or vegan.
• Baking powder – baking powder really helps the oat mug cake rise when cooking. Be sure to use fresh baking powder (opened in the last 6 months) for the best rise. Note that if you don’t have baking powder, you can still make this, the mug cake just won’t rise as much during baking.
• Chocolate chips (optional) – chocolate chips add a fun element to the mug cake, but they are 100% optional. Check out the list below for other add-in ingredients as well.

How to make oat flour mug cake

Start by combining the avocado oil, coconut sugar and vanilla extract in a 8-10 oz. mug. Stir well.

Add the oat flour, dairy free milk and baking powder to the mug with the coconut sugar mixture. Stir well until all the lumps are gone from the oat flour.

Add in the chocolate chips (optional).

Cook on high power in the microwave for 60 seconds. After cooking, allow the mug cake to cool for 2-5 minutes for the best texture.

Top tips

• Be sure you are using fresh baking powder to ensure that your mug cake rises as much as possible. Baking powder starts to lose it’s rise within about 6 months.
• If you are using a large mug, don’t expect the mug cake to look very tall. I tested this recipe in a 10oz mug and photographed it in an 8oz mug.
• Let the oat mug cake rest for 2-5 minutes before enjoying to ensure the best texture. This allows the center to set a bit while the outside of the cake cools slightly.
• If you do not have oat flour on hand, you can make your own oat flour by grinding up oats in the blender or you can measure out 1/3 cup of rolled oats or quick cooking oats into a blender with the rest of the ingredients (except the chocolate chips) and blend well until smooth. Pour this batter into a mug and cook on high in the microwave.
• Use a glazed ceramic mug with a shiny finish or an oven safe ramekin to help ensure the mug cake can rise well, Using unfinished pottery may prevent the mug cake from rising.
• As the mug cake cools, it will lose some of it’s rise. It will be the highest it is going to get while it’s cooking in the microwave and it will start to fall as it cools. This is normal and expected.

Other additions

• Chopped nuts – pecans, walnuts, cashews, peanuts, pumpkin seeds
• Dried fruit – raisins, dried cranberries, dried cherries, chopped pitted dates
• Fresh fruit – blueberries, cherries, strawberries, raspberries, blackberries
• Coconut flakes
• White chocolate chips or peanut butter chips
• Peanut butter cups (cut into chunks)
• Spices: cinnamon, nutmeg, pumpkin pie spice
• Orange zest, lemon zest

Topping ideas

• Nut butter: Peanut butter, almond butter, cashew butter, sunbutter, tahini
• Fresh fruit: chopped strawberries, cherries, blueberries, raspberries, sliced bananas
• Sweetness: Maple syrup, honey or date syrup
• Coconut flakes or coconut butter
• Frosting: Cashew maple frosting, greek yogurt frosting (combine 1/4 cup greek yogurt and 1-2 tablespoons maple syrup)
• Tahini chocolate spread
• Whipped cream – regular or dairy free
• Ice cream
• Jam or jelly – add a spoonful of strawberry jam or raspberry jelly to the top for a fun twist on a jelly filled donut
• Sprinkles

Common questions

Can you make a oat mug cake in the oven?

If you prefer not to use the microwave, you can bake this oat flour cake in the oven in oven safe ramekins at 350F for 15-20 minutes.

Can you make a mug cake in the air fryer?

Yes. Use an oven safe ramekin and bake in the air fryer at 345F for 8 minutes. Let it rest for 5 minutes before enjoying.

What if my mug cake doesn’t look cooked in the center?

This oat flour mug cake recipe doesn’t have any eggs and is using the power of baking powder to rise. Because of this, the outside of the mug can get hotter and cook quicker than the center.

I find that typically letting the mug cake rest for about 5 minutes helps to allow the center to cook while the outer rim of the cake cools slightly, giving the entire mug cake a similar texture and doneness.

However, if you find that even after resting the mug cake still had a soft center, you likely need to cook it for an additional 15-20 seconds next time you make this recipe.

Note that since this is egg-free, it’s safe to eat the mug cake even if the center is a little soft.

Why did the oat cake turn out hard or rubbery?

The texture of the oat flour mug cake depends a lot on cooking time. You want to cook the batter until it’s just set, not overcook it. If the oat flour cakes get overcooked, they can get tough and have an almost rubbery texture. To avoid this, I recommend that you cook the recipe as written the first time and allow it to cool to see how your microwave does.

If the mug cake was gooey or too soft in the center, add 10-20 seconds. If it was too hard or became rubbery, reduce the cooking time to 50 seconds.

Once you have tested this once or twice, you will know the exact time your microwave requires to make this perfectly every time.

What if you don’t have oat flour?

If you don’t have oat flour on hand, you can always make your own oat flour by blending up oats (regular or quick cooking) in the blender or in a food processor. I find that homemade oat flour never gets quite as fine as store bought, so add an extra 1/2 tablespoon of homemade oat flour to the recipe.

Alternatively, you can simply make this recipe in the blender with rolled oats or quick cooking oats (about 1/3 cup) in place of the oat flour. Simply add all the ingredients to the blender and blend on high until smooth. Pour into a mug and cook in the microwave.

I don’t recommend substituting the oat flour with any other gluten free flours, as the oat flour has a very distinct texture, flavor and consistency when baked.

Can you make this oil free?

Without oil, you run the risk of this mug cake being “too cakey” and spongy in texture. The oil really helps to coat the oat flour and give it the perfect soft but tender consistency I really love. If you are avoiding oils, you could try adding runny almond butter or tahini in place of the oil but the texture stil may not be exactly the same.

Can you double the recipe?

If you want to make 2 mug cakes, simply measure out the ingredients in each individual mug and microwave each separately. Don’t microwave them together.

If you are trying to make an even bigger mug cake, double the ingredients, use a larger mug and microwave for 1:30-2 minutes.

Storing leftovers

This recipe was written to be a single serve dessert that you enjoy right after cooking. If you know you want to make this in advance and store it for later, I recommend that you make it without the baking powder. This means that the cake won’t rise as much, but I find that the slightly denser texture is really delicious after allowing the mug cake to cool.

Fridge: Allow the mug cake to cool completely on the counter, then cover and store in the fridge for up to 2 days.

Freezer: I have not tried freezing leftovers.

Substitutions

• Avocado oil – use any oil that you have on hand, olive oil, melted coconut oil, melted butter, melted ghee or runny almond butter or tahini.
• Coconut sugar – use maple sugar, brown sugar or white sugar in place of the coconut sugar.
• Oat flour – you can make your own oat flour by blending up oats in the food processor or blender or make this recipe in the blender with rolled oats or quick oats in place of the oat flour. Use about 1/3 cup of rolled oats in place of the oat flour and blend until smooth.
• Dairy free milk – use whatever dairy free milk you have on hand. You can also use regular dairy if you are not dairy free or vegan. If you don’t have milk, use water.
• Baking powder – baking powder will help your oat flour mug cake rise. If you don’t have it, simply omit, just know that the mug cake will be a little more dense in texture.
• Chocolate chips – use whatever add in ingredients you love from the list above.

If you love this recipe, you should try

Oat Flour Sugar Cookies

Pumpkin Oat Flour Cookies

Oat Flour Chocolate Chip Cookies

Oat Flour Brownies

Oat Tortillas