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!

Easy Oat Cake in a Mug
If you are looking for a healthy and affordable gluten-free baking alternative, using oatmeal or homemade oat flour has become a favorite option of mine. Because oats simultaneously build structure and acts as a binder, 100% oat recipes require no flour!
Oatmeal mug cake is no exception. Using only simple ingredients, such oats, milk, egg, maple syrup (or brown sugar), oil, and baking powder, means you can enjoy this treat whenever the fancy strikes. And, like almond flour mug cake, it can easily be modified for dairy-free or sugar-free.
Flourless oatmeal mug cake not only makes a lovely dessert option, but may also be served as a delicious gluten-free breakfast, which kids particularly love. Instead of topping with chocolate chips, whipped cream or ice cream, dollop on a scoop of peanut butter, chopped nuts, or fresh berries.
Below I will show you how to make oatmeal mug cake, along with 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!
Ingredient Notes
Mug cake recipes are particularly great for different dietary needs and preferences. Use the suggested substitutions and variations listed below for a gluten-free mug cake, dairy-free, healthy, or even protein-rich.
- Egg – Using one whole egg best mimics the texture of cake. However, for a vegan or egg-free option replace with 1/2 mashed banana. Please note, the texture will be more liked 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. To add protein or a nutty flavor, substitute an equal amount of creamy peanut butter, but this also results in a slightly more dense texture.
- Sweetener – Using pure maple syrup yields the best results. Brown sugar or coconut sugar will also work, but may dry out texture. If making a breakfast mug cake or a healthy dessert, you may also reduce the amount of 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. Old fashioned rolled oats may be used, but the crumb will be heavier and more rustic. For a gluten-free mug cake, 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.
- Chocolate chips – Optional, but tasty! Using miniature chocolate chips stays more evenly dispersed throughout the batter. They may also be omitted for dairy-free or a healthier alternative.
how to make Oatmeal Mug Cake
(Below shows step-by-step photos and modified instructions. For the complete recipe, along with ingredient amounts, scroll down to the recipe card.)
- Grease a 10 ounce microwave-safe mug or ramekin with nonstick cooking spray. Use a fork to whisk together the wet ingredients – egg, maple syrup, oil, milk, and vanilla extract.
- Stir in the dry ingredients – oats, baking powder, cinnamon, and salt. If using chocolate chips, do not add them yet.
- Pour the cake 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.
- 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.
Click here to see the
step-by-step web story instructions for this 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!
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.
Mug Cake Toppings
For best taste, enjoy warm out of the microwave oven. To make this a truly decadent dessert, top with one of the suggested toppings below. To serve for breakfast, choose healthier options such as fruit or nuts.
While the single serving size helps portion control, it can easily be divided into two servings, especially when adding toppings.
- Peanut butter or any preferred nut butter
- Sliced bananas
- Ice cream
- Fresh berries, such as strawberries, blueberries, or raspberries
- Nuts, such as almonds, walnuts, or candied pecans
- Whipped cream
- Chocolate sauce or hot fudge
- Coconut
- Quick glaze frosting – mix together 1 tbsp powdered sugar, 1 tsp milk, dash of vanilla extract.
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.
Save this recipe for Oat Mug Cake to your pinterest board!
Let’s be friends on Pinterest! I’m always sharing great recipes!
2 Minute Oatmeal Mug Cake (Fluffy, No Flour)
Ingredients
- 1 large egg
- 3 tablespoons milk or dairy-free alternative
- 2 tablespoons pure maple syrup preferred, see recipe notes for subs
- 1 tablespoon oil canola, vegetable, or melted coconut oil
- ½ teaspoon vanilla extract
- ½ cup quick-cooking oats certified gluten-free for GF cake
- ½ teaspoon baking powder
- ¼ teaspoon ground cinnamon
- ⅛ teaspoon salt
- ½ tablespoon miniature chocolate chips optional
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.
- DID YOU MAKE THIS RECIPE?? DON'T FORGET TO LEAVE FEEDBACK AND/OR CLICK A STAR RATING ON THE RECIPE CARD!
Recipe 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
Nutrition
This post contains affiliate links. My opinions are always my own. If you purchase a product through an affiliate link, I make a small commission – at no cost to you. Read full disclosure policy here.
Teresa says
I think this recipe needs a lot of individual tweaking as the final product depends a lot on the wattage of your microwave, the size of the egg, how finely the oatmeal is ground. The taste is good, but I followed the recipe exactly and mine turned out too dry. The longer it sits the drier it gets. Maybe a good idea to add more milk at the end?
Melissa Erdelac says
Hi Teresa,
You are right the wattage of the microwave will make a difference, just like in any recipe with microwave directions. Since I only have the one in my kitchen to test recipes, I can’t explicitly say how different wattage microwaves will adjust the baking time. If it helps, mine is a 1000 watt oven so you can make adjustments from there. I’m curious about the oats. Did you use oat flour or quick oats? Generally quick oats are a pretty uniform size, but yes oat flour can be different consistencies, especially if you are grinding it at home. Adding a little more milk would help offset a dry texture.
Best,
Melissa
Angie says
I only had oat flour, so I used a tiny bit less than called for and this was great. A bit more than one serving for me, but very tasty and quick. Genius tip to stir it. I wasn’t sure it would work since it had started solidifying, but it came out so uniformly soft and cakey!
Melissa Erdelac says
Thanks, Angie! Yes, when I make this I can’t eat it in one serving either, but at least you don’t have a whole cake sitting around tempting you! Glad you enjoyed the tip.
Best,
Melissa
Tracy Thessing says
Can you use old fashioned oats? It’s all I have.
Melissa Erdelac says
Hi Tracy, Yes, you can. The texture will just be a little different, a little more rustic, not quite as fluffy, but the taste will still be good!
Best,
Melissa
Joansy says
I made this for breakfast today. It was delicious! I used milk chocolate chips, more than half a tablespoon, because I’ll be 70 next month and I felt like it. And I think more chocolate helps make up for having to eat gluten free. Except for that, I followed your recipe exactly. Thanks for sharing your yummy recipes, I have made several of them and all have been delicious.
Melissa Erdelac says
Thanks Joansy! I agree about the chocolate factor. I typically don’t measure chocolate because how can a little more ever hurt??
Best,
Melissa