Hot Chocolate Mug Cake in the Microwave
A hot chocolate mug cake is a single cocoa cake stirred together in a large mug and cooked in the microwave in 70 to 90 seconds. Milk chocolate chips go in the batter and on top, so it tastes like a cup of hot cocoa turned into cake. It takes about 7 minutes from start to spoon and has about 760 calories, so it is a generous treat to share between two.
Quick answer
Whisk 4 tbsp flour, 3 tbsp sugar, 1 tbsp cocoa, 1/4 tsp baking powder and a pinch of salt in a 12-ounce or larger mug. Stir in 3 tbsp milk and 2 tbsp oil, fold in 2 tbsp mini milk chocolate chips, and microwave on high for 70 to 90 seconds. Scatter 2 tbsp chips on top and rest 2 minutes. Total time about 7 minutes.
Hot Chocolate Mug Cake
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Hot Chocolate Mug Cake Ingredients
- 4 tbsp all-purpose flour
- 3 tbsp granulated sugar
- 1 tbsp unsweetened cocoa powder
- 1/4 tsp baking powder
- Pinch of salt
- 3 tbsp milk
- 2 tbsp neutral oil
- 1/4 tsp vanilla bean powder (optional)
- 2 tbsp mini milk chocolate chips, for the batter
- 2 tbsp mini milk chocolate chips, for the top
- Whipped cream, to serve (optional)
How to Make a Hot Chocolate Mug Cake
- In a microwave-safe mug that holds at least 12 ounces, whisk the flour, sugar, cocoa, baking powder and salt with a fork.
- Add the milk, oil and vanilla bean powder (if using). Stir until smooth, scraping the bottom edge of the mug.
- Fold in the first 2 tbsp of chocolate chips.
- Microwave on high for 70 seconds in a 1,000–1,100-watt microwave (up to 90 seconds in a lower-wattage one), until the cake has risen and the top looks set with a small soft spot in the center.
- Scatter the remaining chocolate chips over the hot top so they melt into a glossy layer.
- Let the hot chocolate mug cake rest for 1 to 2 minutes before eating; the mug and the center are very hot. Add whipped cream if you like.
Nutrition Facts
Per mug cake (estimated; share between two for about 380 calories each)
- Calories: 760
- Total fat: 42 g
- Saturated fat: 11 g
- Cholesterol: 15 mg
- Sodium: 320 mg
- Carbohydrates: 92 g
- Fiber: 4 g
- Sugar: 62 g
- Protein: 9 g
Estimated from USDA FoodData Central SR Legacy values for flour, sugar, unsweetened cocoa (FDC 169593), baking powder, whole milk, canola oil and milk chocolate (FDC 167587, 42 g for 4 tbsp mini chips). The optional whipped cream and vanilla bean powder are not included.
How Long to Microwave a Hot Chocolate Mug Cake
Microwave power is the biggest variable. Most full-size microwaves are 1,000 to 1,200 watts, and compact ones can be 700 to 900. Start low and add 10-second bursts; the hot chocolate mug cake keeps cooking for a minute after it comes out.
| Microwave power | Start at | Done when |
|---|---|---|
| 1,100–1,200 W | 60–70 seconds | Top looks set, small soft spot in center |
| 900–1,000 W | 70–80 seconds | Same cue |
| 700–800 W | 85–90 seconds | Same cue; add 10 seconds if wet |
Why This Hot Chocolate Mug Cake Is Fluffy, Not Rubbery
Mug cakes turn rubbery when they overcook, because the small amount of batter dries out fast. This one uses a little more flour and oil than a brownie-style mug dessert, which gives a cake-like crumb, and it comes out while the center still looks slightly soft. Oil keeps the crumb tender after it cools a little, which butter does less well.
Adding the chips in two stages gives the cocoa flavor two ways: melted pockets inside and a glossy chocolate layer on top, like the skin on a mug of hot chocolate.
Can You Use Hot Cocoa Mix?
Yes. Swap the cocoa powder and sugar for 3 tbsp hot cocoa mix plus 1 tbsp sugar; most mixes are already sweet and contain milk powder. The cake will be a little paler and sweeter than one made with plain cocoa.
Tips for a Better Hot Chocolate Mug Cake
- Use a big mug. The batter roughly doubles as it cooks, so a 12-ounce mug is the minimum.
- Stir out the flour pockets. Dry flour hides in the bottom edge of the mug; scrape it with the fork.
- Stop early. Pull it at the shortest time, check, and add 10 seconds only if the top is still wet.
- Swap the chips. Semisweet or dark chocolate chips work the same way and make it less sweet.
Is Raw Mug Cake Batter Safe to Eat?
No. The FDA says flour is a raw food that can carry bacteria such as E. coli, and that you should never eat or taste raw flour, dough or batter. This recipe has no egg, but the flour still needs cooking. Make sure the center is cooked through; a small soft spot on top is fine, but liquid batter under the surface means it needs 10 more seconds. See the FDA guide to handling flour.
Make-Ahead Mug Cake Mix
A hot chocolate mug cake is best eaten right away; it turns firm as it cools. To prep ahead, measure the dry ingredients into small jars and keep them in the pantry. When you want one, tip a jar into a mug and add the milk, oil and chips.
For a baked version of the same idea, try the single-serve brownie, or pair the mug cake with a cold chocolate ice cream scoop.
Hot Chocolate Mug Cake FAQ
Why did my hot chocolate mug cake overflow?
The mug was too small. Use one that holds at least 12 ounces.
Why is my mug cake rubbery?
It cooked too long. Microwaves vary, so start at 60–70 seconds and add short bursts.
Can I make a hot chocolate mug cake without a microwave?
Yes. Bake the batter in an oven-safe ramekin at 350°F for about 12 to 15 minutes, until the top springs back.
How many calories are in a hot chocolate mug cake?
About 760 calories for the whole mug without whipped cream, based on USDA FoodData Central values, or about 380 if you share it.
Can I add an egg?
You can add 1 egg yolk for a richer, more custardy cake. Cook it until the center is set, and don’t eat it underdone.
Sources
Featured photo: Unsplash
