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 know you'll love this oatmeal mug cake, too, 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!
Jump to:
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!
RELATED: Love quick and easy mug treats? Don't miss these microwave desserts: banana mug cake, vegan mug brownie, apple crisp in a mug, and microwave granola!
Ingredients
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.
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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.
Substitutions
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 dollop of creamy non-dairy yogurt pairs perfectly with this oat mug cake. Top it with fresh berries plus hemp seeds, chopped walnuts or pecans.
And don't forget a tall glass of oat milk to wash it down! Or if you're in the mood for coffee with your mug muffin, try my homemade oat milk creamer.
This oatmeal mug cake also makes a great dessert! Pair it with a scoop of oat milk ice cream, extra maple syrup, or this vegan chocolate sauce!
Recipe FAQs
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 dial in the perfect cook time for your appliance.
It's generally not a good idea to replace a primary ingredient in any recipe, especially with 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.
Top Tip
Even though mug cakes are quick and easy to prepare, it's essentially still "baking." So it's important to measure accurately, and keep a close eye on it until you figure out the exact cook time for your microwave.
More Oat Flour Recipes You'll Love
- Double-Chocolate Oat Flour Cookies
- Vegan Pistachio Muffins
- Oat Flour Pancakes
- Oat Flour Banana Bread
- Gluten-free Vegan Peanut Butter Cookies
- Tahini Oatmeal Cookies
I hope you enjoy this oil-free oatmeal mug cake. Comment below to share your feedback, and let us know if you try any fun flavors, additions, or spices!
Recipe
Healthy Oatmeal Mug Cake (Vegan)
Ingredients
Wet ingredients:
- 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
Dry ingredients:
- ⅓ cup fine oat flour - tap "metric" above for weight
- ½ teaspoon pumpkin spice blend or cinnamon
- ¼ teaspoon baking powder
- pinch of sea salt
Instructions
- 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.
Notes
Estimated Nutrition (per serving)
Nutrition information is an estimate and will vary depending on the exact amounts and specific products and ingredients used.
TJ says
I've made this a few times with less sweetener and the addition of frozen raspberries — so insanely good, thank you!
Vada Spence says
I made this because I was craving a warm dessert. It is so moist and delicious! I love that it’s healthy too! I’m definitely making it again.
Jodi Clark says
I was really craving something sweet the other night and stumbled upon your recipe. Can I just say, this was so simple and delicious! It really hit the spot! I used a pumpkin spice blend and it was such a nice change from the usual chocolate. Thanks for sharing!
Kim says
I really, really enjoy this recipe. I use a full teaspoon of cinnamon or pumpkin pie spice as i like a bit more spice flavir. I made an alternative that uses buckwheat. I up the milk to 3 tablespoons as buckwheat absorbs moisture more. It worked with 2 but was a bit too dry. Thanks for sharing.
Gerry P says
Thank you for this recipe. I'm looking for a dessert recipe where I can feel good about it and it's easy. The flavor was yummy, and it was dense for me. I don't know if it's over-cooked (it didn't seem dry to me). My baking powder is just under 6 months old. I did 90 seconds (in intervals) as my microwave is 950w. I also wonder if may have done too full of a tbsp of peanut butter?
Any thoughts?
Lori says
Hi Gerry, sorry about the delayed response! We were on vacation and I missed your question. You may be right about the nut butter, or maybe you just needed a bit more flour or less milk. It's difficult to say. With another try I bet you can dial it in and get the texture exactly where you want it!
Laura says
Wow!! I love this recipe. I used as a template to meet my dietary needs and it didn’t disappoint! I used tahini, full fat coconut milk, replaced 1 Tbsp of maple syrup with 1 Tbsp of St Dalfour (all fruit) blueberry jam and buckwheat flour in place of oat flour. I love nutmeg and cardamom so I used the two for my spice. I went with your 70 second suggestion. It was perfectly light and fluffy, amazing flavor and super satisfying. Thank you so much!!
Lauren says
Also wanted to say thank you! I have A LOT of food allergies so this was awesome.
Lauren says
This recipe was great! Loved it. I love apples so I added diced fried apples on top. Just so good. Also, the measurements were perfect.
Kat says
Saved to try! 🙂 Always looking for good mug muffin recipes. With new food allergies cropping up all the time, first dairy then gluten and most recently eggs, I've tried many! Last few years of working with egg free recipes (for mug muffins) I've noticed that once it looks done it is actually overcooked! For the most moist muffin, the very center should still look a bit too wet / moist. Then let it sit for 5 minutes, and the carryover cooking will finish it! 🙂 Just wanted to add that tip, in case it helps anyone else on this learning curve. 🙂 (Oh! & p.s. Coffee creamer can be used in place of the milk / liquid and can add some some interesting flavors.)
Julie McKay says
Hi! This recipe is really yummy. I've made it a few times. My problem is I can't get it to rise nearly as much as your picture. I am using a 10 oz mug and following your instructions exactly with all the same ingredients. Do you have any suggestions to help it to get fluffy and rise as much as yours?
Thanks!
Lori says
Hi Julie, I'm glad you like it! As far as the rise, is there any chance the baking powder you're using is old? It does lose effectiveness over time, so that would be my first guess. It could possibly have to do with differences in microwaves, but if yours is done in about the same amount of time as mentioned in the recipe, then I don't think that would be it.
varvas says
i'm obsessed! thank you so much for sharing <333
Jen says
Can u just use regular flour?
Lori says
You can always experiment, but I think it would probably be better to use a mug cake recipe written specifically for regular all-purpose flour. With recipes like this (small amount, few ingredients), substitutions tend to make a pretty big difference.
Pam in Sacramento says
I've made this several times now (used almond butter). It reminds me of a spiced oat muffin. I love it. The texture is perfect and it turns out just right each time.
And even better, I like that I can make and eat ONE muffin, rather than make and eat a dozen.
Thank you, Lori!