Rich, chocolatey brownie in a mug topped with melted chocolate and m&ms, an indulgent take on little Debbie's cosmic brownies that comes together in less than 5 minutes.
What is a cosmic brownie?
Cosmic brownies were originally created by little Debbie's. They are chewy and fudgy chocolate brownies topped with fudge frosting and crunchy rainbow chocolate sprinkles.
They were a staple in childhood lunchboxes, and an all-around favorite childhood treat!
This version takes inspiration from the cosmic brownie. But instead, we are making it in a microwave so you can fix those chocolate brownie cravings ASAP. This microwave brownie recipe is so good you won't be able to tell that it comes together in less than 5 minutes!
Ingredients in a mug brownie
The ingredients needed in this brownie are pretty much all pantry staples. Here's a run-down of all the ingredients you need!
- Unsalted butter: Melted butter gives these a delicious fragrance and plush texture. Make sure you use unsalted butter to prevent it from being too salty.
- Dark chocolate: I like to use real chocolate over cocoa powder for a fudgier texture!
- Granulated sugar: The sugar will give this cake its sweetness in conjunction with the chocolate. I wouldn't change the amount used by much as it can affect the texture of the final brownie.
- Whole milk: Milk adds moisture to the batter!
- All-purpose flour: Flour is needed to give this cake structure and its cake-like crumb
- Baking powder: A little baking powder helps give the brownie a bit of rise, preventing it from being super rubbery or hard.
- Melted chocolate: This is optional but it really gives it a deeper chocolate flavor.
- M&Ms: I like using m&ms because they resemble the chocolate on cosmic brownies. If you can find what they use feel free to use that, or whatever you have in your pantry.
There are so many different ways to serve this single-serve brownie!
Of course, the default is melted chocolate and M&M's for that cosmic brownie recreation, but here are a couple of my favorite other ways to serve this. And since this is a single serving dessert you are free to serve this the way YOU want!
- A scoop of vanilla ice cream: Ice cream and brownies is the ultimate combination. You can't go wrong with a scoop of creamy ice cream
- Peanut butter: Replace the melted chocolate with melted peanut butter for a choc-peanut brownie mug cake!
- Nuts: Top with melted chocolate and chopped roasted nuts for a nutty rendition. My favorite nuts to add are peanuts, walnuts, pecans, or hazelnuts!
- Chocolate chips: Mix chocolate chips into your brownie batter for a triple chocolate experience! The chocolate will melt as the brownie cooks for a gooier experience.
- Caramel: Replace the melted chocolate with caramel for a choc-caramel brownie. Dulce de leche works too!
- Fresh fruits: Fresh fruits always taste delicious and help cut through the sweetness of a brownie. Try adding berries like raspberries or strawberries!
Frequently Asked Questions
How long do mug cakes last?
Mug cakes are best the day they are made as they will become stale as they sit. I find that these are best when warm for a softer, gooier brownie texture, and when cooled for a fudgier denser brownie.
Can I make a mug cake ahead of time?
If you want to eat these warm I recommend making them when you are ready to eat. Since these are made in the microwave they don't take very long to make anyway!
If you want to have a fudgy brownie you can make these ahead of time and let them cool. I wouldn't make them more than a day in advance though!
Why is my brownie rubbery?
These can turn it rubbery if too much milk or butter is added. Make sure you measure out the ingredients when making these to prevent this from happening!
Why is my brownie dry?
If your brownie turned out dry and crumbly it was most likely overcooked. Check on your brownie after 1 minute in the microwave.
The center should look just set. It's okay if it isn't fully cooked through as a gooey brownie is the best way to eat a brownie anyway!
Can I make these in the oven?
If you don't have a microwave you can make the batter and bake it in a ramekin in the oven. I would bake them for 10-13 minutes in an oven preheated to 180C/350F.
Let's Get Baking
If you are looking for an easy mug brownie recipe to satisfy those chocolate cravings this cosmic brownie in a mug is the recipe for you! Grab your microwave-safe mug and get cooking!
If you liked this recipe make sure to leave me a comment and rating down below, I would love to know how you went.
Also, don't forget to tag me on Instagram @catherine.desserts and hashtag #cattycakes so I can see and share your desserts. Follow me on Facebook, Pinterest, Youtube, and TikTok for more of my baking creations and updates! Until next time... happy caking!Print
Cosmic Brownie in a Mug
Rich, chocolatey brownie topped with melted chocolate and m&ms, an indulgent take on little Debbie's cosmic brownies that comes together in less than 5 minutes.
- Prep Time: 5 minutes
- Cook Time: 2 minutes
- Total Time: 7 minutes
- Yield: 1 Mug Cake 1x
- Category: Cake
- Method: Easy
- Cuisine: American
- 2 tbsp Unsalted butter
- 30g Dark chocolate (1 oz) (approx 6 squares)
- 2 tbsp Granulated sugar
- 2 tbsp Whole milk
- 4 tbsp All-purpose flour
- ¼ tsp Baking powder
- Melted chocolate and m&ms for decorating
- Combine the butter and chocolate in a mug and microwave for 30 seconds until melted
- Add the sugar, milk, flour and baking powder, mix until combined
- Microwave for 1 minute to 1 minute 30 seconds
- Top with melted chocolate and m&ms
Keywords: little debbie's brownies, cosmic brownies, microwave cake, easy cake