Looking for an easy gluten-free breakfast or snack to make in minutes? Whip up this fluffy oatmeal cake in a mug with no flour required, only oats! Using my simple hack, stirring halfway through, means a light, fluffy, yet moist, texture every time! Oat mug cakes use simple ingredients, right in your kitchen, so you can enjoy this treat right now, in only 2 minutes!

a bite taken out of the cake with a spoon resting next to it.
Whether you are looking for a single-serving gluten-free dessert, snack, or breakfast treat, this easy oatmeal mug cake has you covered.

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Game-Changing Oat Cake In a Mug

Why am I oatmeal’s biggest cheerleader?? If you are on a gluten-free diet (and can tolerate GF oats), using oatmeal or oat flour is a game changer. It’s affordable, tasty, and won’t cause you any GF drama! Making a mug cake with oatmeal helps build structure, acts as a binder, and 100% oat recipes require no flour!

To make this oatmeal mug cake just grab some GF oats, milk, egg, maple syrup (or brown sugar), oil, and baking powder. You’re equipped with those, right? So enjoy it whenever the fancy strikes. And, like a fudgy chocolate almond flour mug cake, it can easily be modified for dairy-free or sugar-free.

A flourless oatmeal mug cake not only hits when the sweet tooth strikes, but can objectively be considered hearty enough for an easy gluten-free breakfast idea. Want to go all out? Instead of topping with chocolate chips, pile on whipped cream, ice cream, a scoop of peanut butter, chopped nuts, or fresh berries.

Although this recipe doesn’t require any immense cooking / baking skills, just a desire, below I touch on workable ingredient swaps, tips for preventing a rubbery cake, topping ideas, along with many easy tips to make a perfectly fluffy oat cake in a mug every time!

This👏🏼is👏🏼SO👏🏼delicious! Can’t even lie, I make this every other night and I have no regrets😏😋😏

—Erica

Ingredient Tips and Subs

  • Egg – Using one whole egg best mimics the texture of cake. For an egg-free option replace with 1/2 mashed banana. I found when try this, though, the texture was more like baked oatmeal than cake.
  • Oil – Also ideal for a fluffy cake texture, but any preferred oil may be used, such as canola or melted coconut oil. You can also swap out an equal amount of creamy peanut butter, but it will have a slightly more dense texture.
  • Sweetener – When testing the recipe I found pure maple syrup made for the best results. Brown sugar or coconut sugar will also work, but dries out texture slightly. If making this for breakfast or a light dessert, you may also reduce the sweetener. I have not tried this recipe with a sugar-free substitute, but I see no reason why it wouldn’t work as well.
  • Oats – Use quick-cooking oats or oat flour for best results. You can use dld fashioned rolled oats, but the crumb will be heavier and more rustic. For a GF recipe, be sure to use certified gluten-free oats.
  • Milk – For a dairy-free recipe, replace with soy, oat milk, almond milk, or any preferred non-dairy substitute. No issues there at all!
  • Chocolate chips – Optional, but why not?! Using miniature chocolate chips stays more evenly dispersed throughout the batter. You may also leave them out for a dairy-free version.

Let’s Make This Together!

(Below shows step-by-step photos and modified instructions. For the complete recipe, along with ingredient amounts, scroll down to the recipe card.)

Whisk wet ingredients

Key point here is make sure your mug or ramekin is at least 10 ounces or else your 2 minute project will turn into a longer clean up mission. Spray it with nonstick cooking spray and use a fork to whisk together the egg, maple syrup, oil, milk, and vanilla extract.

liquid ingredients to make mug cake.

Stir in dry and magic cooking tip

Now stir in your dry ingredients – oats, baking powder, cinnamon, and salt. If you’re using chocolate chips, do not add them yet or they will get all melty. But go for it if you are looking for a chocolate oat version. Ready for the magic? Cook for 45 seconds at full power. Remove and stir again. This helps the egg disperse, not settle to the bottom, and avoids rubbery results. Then return to the microwave for 45-60 seconds more. Wait long enough to not burn your mouth (or not) and enjoy!

adding the dry ingredients to the recipe.

Recommended Oats or Using Oat Flour

Since oat mug cakes have a short cooking time, it’s essential to use fine, smaller, quick-cooking oatmeal for the fluffiest results. Quick oats absorb the liquids better in the short cooking time.

Another option would be to substitute an equal amount of oat flour. An oat flour mug cake would have an even more cake-like texture, so if you have it on hand, give it a try!

If you don’t have any in your kitchen, you can still easily make it in seconds, though. Place ½ cup quick or rolled oats in a blender. Blend for 30-45 seconds, or until no large flakes appear. Voila! Replace for the oats to make an oat flour mug cake in minutes!

a spoon of the cake on a white background.
Boost the sweetness by stirring in chocolate chips or serving with whipped cream. Boost the wholesomeness with fresh berries, chopped nuts, or swirling in peanut butter.

How To Avoid Rubbery Mug Cakes

Most mug cake recipes require an egg, which can become rubbery when cooked in the microwave. So how can we avoid this unpleasant texture in an oatmeal mug cake?

Easy! To avoid a rubbery cake, use a fork and stir the batter halfway through cooking. This will evenly distribute the egg throughout and absorb into the other ingredients. Also, be sure to not overcook, which causes too much moisture to evaporate.

Seriously Delish Toppings

It’s best enjoyed warm, and frankly as is works great, but it’s hard to not dream up some tasty toppings. For a next level decadent dessert, dollop a scoop of ice cream, whipped cream or event hot fudge on top.

If making this for breakfast or a lighter dessert, I usually go for fresh berries, nuts, coconut, sliced bananas, or even a scoop of peanut butter.

While the single serving size helps portion control, it can easily be divided into two servings, especially when adding toppings. But if you’re looking to super-size your dessert (who isn’t?!) this 5-minute blender oat flour cake with brown sugar frosting checks all the boxes!

overhead shot of mug cake in a green dish with berries around.
“Baked to perfection” all in two minutes with a little help from a microwave. An easy, satiating treat at its best!

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Did you make this recipe? I love hearing from you! Leave a star rating and comment below the recipe card. It helps others when searching for recipes and I appreciate feedback from our community. You will always hear back from me! -Melissa

a bite taken out of the cake with a spoon resting next to it.
4.54 stars (65 ratings)

2 Minute Oatmeal Mug Cake (Fluffy, No Flour)

Melissa Erdelac of MamaGourmand headshot in patterned dress.Melissa Erdelac
Yield: 1
Prep Time: 1 minute
Cook Time: 2 minutes
Total Time: 3 minutes
Looking for an easy gluten-free treat to make in minutes? Whip up this fluffy oatmeal cake in a mug with no flour required, only oats! Using my simple hack, stirring halfway through, means a light, fluffy, yet moist, texture every time! Oat mug cakes use simple ingredients, right in your kitchen, so you can enjoy this dessert (or breakfast) right now, in only 2 minutes!
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Ingredients
 

Instructions
 

  • Grease a 10 ounce microwave-safe mug or ramekin with nonstick cooking spray. Use a fork to whisk together egg, milk, maple syrup, oil, and vanilla extract.
    1 large egg, 3 tablespoons milk, 2 tablespoons pure maple syrup, 1 tablespoon oil, ½ teaspoon vanilla extract
  • Using the fork, stir in the oats, baking powder, cinnamon, and salt. If using chocolate chips, do not add them yet.
    ½ cup quick-cooking oats, ½ teaspoon baking powder, ¼ teaspoon ground cinnamon, ⅛ teaspoon salt
  • Pour the batter into the prepared mug. Place in the microwave and cook for 45 seconds at full power. Remove and use a fork to stir the batter until uniformly mixed again. This helps the egg disperse, not settle to the bottom, and avoids rubbery results. If adding chocolate chips, add now and briefly stir to disperse.
    ½ tablespoon miniature chocolate chips
  • Return to the microwave and cook 45-60 seconds more. There will still be a little moisture at top, and that is fine. It will absorb as it sits for 1 minute before serving. Avoid over cooking for best texture.

Notes

Sweetener Options
Using pure maple syrup yields the best results. Brown sugar or coconut sugar will also work, but may dry out texture. You may also reduce the amount of sweetener to 1 or 1½ tablespoon. I have not tried this recipe with a sugar-free substitute, but I see no reason why it wouldn’t work as well.
 
Helpful Tips to Remember
  • Make sure you have at least a 10 ounce mug or ramekin to cook the cake in. Of course, it should be microwave-safe!
  • Stirring the cake halfway through cooking ensures the egg doesn’t settle to the bottom and yields fluffier results.
  • If you would like to double the recipe and make 2 servings, use separate mugs and cook separately, not at the same time.
  • The oil may be replaced with an equal amount of creamy peanut butter, or any preferred nut butter. The cake will be slightly more dense, not quite as fluffy, but still delicious.
  • For leftovers, after it has cooled, wrap securely. For best results, rewarm slightly before enjoying again.
    • Calories: 514kcal, Carbohydrates: 62g, Protein: 13g, Fat: 24g, Saturated Fat: 5g, Polyunsaturated Fat: 6g, Monounsaturated Fat: 12g, Trans Fat: 0.1g, Cholesterol: 166mg, Sodium: 378mg, Potassium: 615mg, Fiber: 5g, Sugar: 30g, Vitamin A: 331IU, Vitamin C: 0.02mg, Calcium: 240mg, Iron: 3mg
    Did you make this recipe?Please leave a star rating and review below. It helps others when searching for recipes and I LOVE feedback!