This oatmeal mug cake is fluffy, tender, just sweet enough to taste like dessert, and healthy enough for breakfast! Think of it like a single-serving oat flour mug muffin that you can whip up in minutes! Delicious served with yogurt or ice cream. Try it with cinnamon for cinnamon roll vibes or pumpkin spice for a festive treat!
This oat mug cake contains no eggs, oil, dairy, gluten, soy, coconut, or refined sugar.
Well, I'm at it again with the oat flour. I really can't explain it, but somehow, every time I start experimenting with any type of baked goods recipe, I just get the most delicious results with oat flour.
Whole wheat flour can sometimes taste a little too "whole-wheat-y" if you know what I mean.
And all-purpose flour can sometimes lean toward gummy when baking without oil (unless you start expanding the ingredient list and making things more complicated).
But I'm a fan of simple.
And the flavor, fluff, and forgiving texture of oat flour just works! For that reason I highly recommend you stick with oats for this recipe if possible.
I think you'll love this oatmeal mug cake because it's:
- naturally sweetened
- light and fluffy
- made with just 7 simple ingredients
- egg-free and dairy-free
- gluten-free (be sure to use certified gluten-free oats or oat flour)
- contains nearly 6 grams of fiber!
- versatile - add chocolate chips or your favorite nuts (pecans taste amazing with the spices!)
- and healthy enough for breakfast!
Also, I have to say, these photos really aren't doing this mug cake justice. It's much more tender, light, and fluffy than it looks in the photos.
And true to its name, it's as easy as any mug cake!
Although, for the best results I do recommend mixing wet ingredients in one mug and dry ingredients in a separate mug, just to make sure there are no clumps and that everything is well distributed.
But after that, simply combine wet and dry ingredients, pop it in the microwave, press a few buttons, and watch it rise!
See the recipe card below for amounts and full instructions. Here's a quick look at the ingredients you'll need:
- oat flour or rolled oats - currently I'm using this oat flour from Anthony's. If you don't have oat flour, simply place rolled oats in the blender and blend until it's the consistency of flour. Look for certified gluten free oats, if needed.
- baking powder - this serves as the leavener and helps the mug cake rise.
- nut butter - any smooth nut butter you like is fine, such as almond, cashew, or peanut. Sunbutter is the best nut-free option.
- non-dairy milk - I used unsweetened almond milk. You could also use coconut, soy, or oat milk.
- maple syrup - the flavor of maple syrup really adds to the tastiness of the oatmeal mug cake. I haven't tried other sweeteners, but a comparable syrup might work. Maple syrup adds moisture, too, so a straight swap with a granulated sweetener won't work.
- spices and vanilla - vanilla extract and your choice of pumpkin spice or cinnamon really make it irresistible!
How to Make Oatmeal Mug Cake
- In a standard, 10-ounce, microwave-safe mug (a larger mug is fine, too), combine the nut butter, milk, maple syrup, and vanilla. Stir really well until it resembles the mixture in the photo above (though the color may be different depending on nut butter used).
- In a separate mug, stir together the oat flour, baking powder, salt, and pumpkin spice or cinnamon.
- Pour the dry ingredients into the wet ingredients, and stir until there's no dry flour.
- Note: my microwave is 1100 watts. Microwave ovens vary. So stay nearby and keep an eye on the mug the first time you try the recipe. Mine come out perfectly when cooked for 70 seconds on high. BUT I recommend starting with just 50 seconds to be on the safe side. Then microwave for another 10 to 20, depending on how much it's rising and whether the center appears firm. If using a smaller, lower wattage microwave you may need to add more time. Do this in 10 to 15 second intervals.
- Let the mug cake rest for 5 minutes before serving.
Haha, "serving." Who are we kidding? We're not serving this to anyone but our own hungry faces.
Can I bake a mug cake?
Yes, if you prefer not to use the microwave, you can bake the mug cake in a 350 degree oven for around 15 to 18 minutes. Just make sure to use an oven-safe mug, ramekin, or other bowl.
And since this is essentially a muffin batter, I'm sure you can also bake it the same way you normally bake oil-free muffins - whether you use a silicone pan or cupcake liners.
I haven't tested the oat mug cake in a metal muffin pan yet, but it should bake faster than in a mug. So keep a close eye on it in the last few minutes just to be safe.
With such a small, specific recipe like this, even tiny adjustments can make or break it.
So while I would love to be able to say you can sub any flour you like, etc, I really can't say that with confidence.
Each ingredient has a purpose, including the maple syrup and nut butter. Though you may use any nut or seed butter you like, so at least there is some flexibility there!
I tested the recipe once using ¼ cup of King Arthur's gluten-free 1:1 blend, and unfortunately, that didn't work out. It cooked up properly and was edible, but the overall flavor needed some adjustments. The gluten-free flour just doesn't taste as good as oat flour.
If you decide to try it, I recommend experimenting with a bit more maple syrup and spice.
Mug Cake Toppings
For breakfast or a snack, a few spoonfuls of creamy non-dairy yogurt pair perfectly with this oat mug cake. Top it with fresh berries and hemp seeds or chopped walnuts or pecans.
If your mug cake has a tough or chewy texture it likely means it's over-cooked. Since all microwave ovens are different, with any mug cake recipe it might take a couple of tries to identify the perfect cook time for your appliance.
It's generally not a good idea to replace a primary ingredient in any recipe, but especially something like a mug cake that has so few ingredients. Of course, it's also just a mug cake! If you experiment with a different flour just understand that it may not work out on the first try. This recipe is written specifically for oat flour and will turn out best if you follow the recipe.
Even though mug cakes are quick and easy to prepare, it is still akin to baking. So it's important to measure accurately, and keep a close eye on it until you figure out the exact cook time in your microwave.
More Oat Flour Recipes
- Double-Chocolate Oat Flour Cookies
- Vegan Pumpkin Muffins
- Cherry-Pistachio Muffins
- Oat Flour Pancakes
- Oat Flour Banana Bread
- Apple-Cinnamon Oat Flour Scones
- Oil-Free Chocolate Cake
- Peanut Butter Cookies
- Spiced Tahini Oatmeal Cookies
I hope you enjoy this oil-free oatmeal mug cake recipe. Comment below to share your feedback, and let us know if you experimented with fun flavors, additions, or spices!
Healthy Oat Mug Cake (Oil-Free)
- 1 very full tablespoon smooth nut butter such as almond, cashew, or peanut butter - Sub seed butter if needed.
- 2 tablespoons non-dairy milk, such as unsweetened almond or oat milk
- 2 tablespoons maple syrup
- ½ teaspoon vanilla extract, optional
- ⅓ cup fine oat flour (34 grams)
- ½ teaspoon pumpkin spice blend or cinnamon
- ¼ teaspoon baking powder
- pinch of sea salt
- In a standard, 10-ounce, microwave-safe mug (a larger mug is fine, too), combine the nut butter, milk, maple syrup, and vanilla. Stir well so that the nut butter is fully incorporated.
- In a separate mug, stir together the oat flour, baking powder, salt, and pumpkin spice or cinnamon. Pour the dry ingredients into the mug with the wet ingredients, and stir until there's no visible dry flour.
- Note: this recipe was tested in an 1100 watt microwave. Microwave ovens vary, so stay nearby and keep an eye on the mug the first time you try the recipe. Begin by microwaving on high power for 50 seconds. Then microwave for another 10 to 20 seconds, depending on how much the cake has risen and whether the center appears firm. In my microwave, this recipe comes out just right with a cook time of 70 seconds. If using a smaller, older, or lower wattage microwave you may need to add more time (do this in 10 to 15 second intervals.)
- Let sit 5 minutes, then enjoy! For breakfast it's delicious with plain vegan yogurt and a sprinkle of hemp seeds. Or if enjoying as a dessert, try it with your favorite vegan ice cream, dairy-free whipped cream, and/or maple syrup.
Estimated Nutrition (per serving)
Nutrition information is an estimate and will vary depending on the exact amounts and specific products and ingredients used. We calculate this information using the online calculator cronometer.com.