This microwave mug cake turns out a perfect little plum upside down cake that bakes in an incredible three minutes and makes just enough to serve one or two. Sorta perfect for when it’s too hot to turn on the oven or you’re too lazy to bake an entire cake.
How To Make Upside Down Microwave Mug Cake (It's SOOOOOOO Easy)
Toss some sliced plums in a mug.
Sprinkle the plums with sugar and spice to make them nice.
Spoon the cake batter into the mug and nuke it for 3 minutes. That’s it.
Microwave Mug Cake
- Quick Glance
- 15 M
- 20 M
- Serves 1 to 2
Special Equipment: 1 large (12 to 16 ounces) microwave-proof flat-bottomed mug
- For the plum topping
- For the microwave mug cake
Cut a piece of baking parchment into a rectangle that’s about 2 inches (5cm) taller than your mug and slightly wider than the circumference of your mug. Slick the mug with some butter and form the baking parchment inside the mug in a cylinder so the paper lies flat against the sides of the mug with the parchment overlapping on the bottom of the mug and extending a couple inches above the rim of the mug.
Arrange the plum quarters in the bottom of the mug. (If you can’t fit all the plum slices in the mug, that’s okay. Just nibble the ones that won’t fit.) Sprinkle the plums with the sugar and cinnamon. If desired, toss the plums with the cinnamon and sugar to coat. Arrange the plum slices with a cut side lying flat against the bottom of the mug.
Place the butter in a heatproof bowl in the microwave and heat on 50% power until melted, 1 to 1 1/2 minutes. Let cool slightly.
Add the flour, sugar, milk, egg, and cinnamon to the melted butter and whisk until everything is incorporated, making sure there are no lumps. The batter may be thick but that’s okay. Scrape the batter over the plums.
Place the mug on a microwave-safe plate in case the cake overflows. Cook in the microwave on full power until the cake springs back when you gently touch it, 3 minutes in a 850- to 1000-watt microwave and 2 minutes in a 1100-watt microwave. (The cake will probably rise above the sides of your mug during baking and then promptly deflate. Don’t worry. This is to be expected. The cake may end up a little lopsided but looks don’t matter nearly as much as taste.) Remove the mug from the microwave and let the cake cool slightly, about 10 minutes.
Remove the paper liner and still-warm cake from the mug and invert the cake into a shallow bowl so the plums are revealed. Discard the paper. Serve the mug cake warm with a dribble of cream or a scoop of ice cream, if desired. (The cake should be eaten on the day it is made and preferably while warm.)
*How To Make Self-Rising Flour
This microwave mug cake recipe requires self-rising flour. You can find this in most grocery stores in the baking aisle next to the all-purpose flour. But if you don’t have a trip to the store in your near future, can also DIY it. To make 1/2 cup self-rising flour, which is just slightly more than you’ll need for the recipe below, simply stir together 1/2 cup all-purpose flour with 3/4 teaspoon baking powder, and 1/4 teaspoon salt.
Recipe Testers' Tips
I love plums but the rest of my family aren't fans so this recipe was perfect for me. I loved the combination of plums and cinnamon and the ease with which the cake came together. The cake was a good texture—just the right amount of loft. It was not at all rubbery or dense like some microwave cakes can be. The cake was nicely sweet which contrasted with the tart plums. I used a 12-ounce mug, which was just barely big enough. My parchment paper stuck out about 2 inches above the edge of the cup and supported the rising cake, but it might have overflowed if I hadn’t had as much extra parchment. I checked the cake after 2 minutes, but it started to collapse, so I quickly closed the door and started the microwave again. After 3 minutes, the cake was set and sprang back when I touched the top. I let it cool about 5 minutes before I tasted it, but it was still hot. After 10 minutes it was the perfect temperature. I drizzled the warm cake with heavy cream, which added a nice bit of richness and creaminess. Ice cream would have been good, too, but it would have added more sweetness, which would have been too much for me. I would like more fruit, maybe even twice as much. (Next time, I might use twice the plums and divide the mixture between 2 mugs to make a couple smaller cakes.) I had some cake left over and ate it the next day. The texture was a little denser than it had been when the cake was warm, but it was still very good.
This yummy mug cake recipe is the perfect solution for when you need a quick fix for that sweet tooth. It's a quick and easy recipe that has you eating cake in 12 minutes! It's also a good basic mug cake recipe—you could leave out the plums and add any other fruit or chocolate to accommodate whatever it is you may be craving. I ended up making two mug cakes so I could use up the extra egg. The plum cooked nicely in the microwave. I do think it could be mixed with the cinnamon and sugar to get it more incorporated. I did get some crispy bits of pure sugar that didn't dissolve or mix in with the plum.
This upside-down plum cake is a fantastic option for dessert on a warm summer evening. You don't have to turn on the oven to enjoy it and you can enjoy it all summer long with different stone fruit as the season progresses. I liked that it was pretty quick to put together and only takes 3 minutes in the microwave to bake. My microwave is 1050W so it may have been done sooner than that, but it wasn't rubbery or overdone when I took it out after 3 minutes. I let the cake cool for 5 minutes, but probably should have let it cool for 5 more minutes. (It was really hot! But we were impatient and didn't want to wait.) The cake had a soft, springy texture and a simple flavor that complemented the sweet, juicy plum topping. We ate the cake unadorned, though whipped cream or vanilla ice cream would have been lovely. I would also, most likely, share this cake with my husband instead of making 2 next time and add a scoop of ice cream to each. It was quite a large portion for me, though he would probably rather have his own.
Freshly “baked” warm cake just for you—if that doesn’t sound delightful, I don’t know what does! I couldn’t have tested this upside-down plum cake recipe at a better time as beautiful stone fruits had just become available at the market and the hot weather was making me reluctant to turn on the oven. I love experimenting (and cake!) so I tested the recipe twice, following the recipe exactly the first time, and with some adjustments the second time. I found that 3 minutes was too long in my 1100w microwave oven; 2 minutes was just perfect. Letting the cake cool for good 5 minutes made a better presentation; the fruit started to slide off the cake immediately when too warm. Lastly, I completely omitted the sugar for the plums the second time. The fruit was plenty sweet and didn’t need any additional sugar. I used 2 black plums and the mug was able to accommodate all the slices.
The word "cake" conjures up a different picture for different people. For many, the word is synonymous with "birthday cake" and this picture consists of two layers and thick frosting. In my family, however, birthday cakes were different. I had the good fortune to be born in early May, so strawberry shortcake was usually my birthday cake of choice. For my mother, however, celebrating a late August birthday meant plum cake. We were lucky that her birthday coincided with the very limited time when tiny Italian prune plums were available in the local market. And even though it meant heating up the oven in summer, plum cake was the order of the day. She would have loved having a recipe that would allow her to have her favorite cake in less time than it would take to preheat the oven. The sponge-like consistency of this cake would let it successfully compete with the more time consuming big cake. And the size is perfect for one or two. I have a 1100-watt microwave. My cook time was 2 minutes, 20 seconds on high power. At that point the cake had shiny damp spots on top but was firm, not liquid. The damp spots disappeared during cooling. This makes 2 servings, especially if served with ice cream.
We ABSOLUTELY loved this little microwaved gem of a mug cake. It takes just a couple of minutes to make and works surprisingly well. It has GREAT flavor. Remember this is a cake baked in a microwave and made in well under 10 minutes, so don't expect a bakery-quality masterpiece. But we found it to have a fine texture and it feeds 2 people nicely. I made this in a 12-ounce ramekin and it was a perfect fit. I finished it with a little homemade whipped cream. The entire affair was delightful!
So easy to make and the perfect recipe for just one! The mug cake is a light sponge with a cinnamon flavor and juicy plums give it a fresh taste. Eat it right after you bake it (just let it cool for a few minutes first).