Homemade Cosmic Brownies — These homemade Cosmic Brownies are dark, dense, and rich. The edges are just a bit chewy, with a moist and ultra-fudgy interior.

Homemade Cosmic Brownies

Homemade Cosmic Brownies Recipe

Growing up, I loved Little Debbie Oatmeal Creme Pies and Cosmic Brownies so much. Show me a box of either, and I could show you a pile of cellophane wrappers minutes later.

Although it’s been years since I’ve had a store-bought Cosmic Brownie, I had a craving for them and decided to try my hand at a homemade version. This isn’t the first Little Debbie snack I’ve recreated. A few months ago I made Homemade Little Debbie Star Crunch and recently posted a collection of 25 Copycat Recipes. Apparently I like trying to re-invent the wheel.

In terms of authenticity, I give these homemade Cosmic Brownies an 8 out of 10, with easy tweaks noted below to bring that score higher.

In terms of being a fabulous brownie overall, I give them a 10 out of 10. This brownie base is likely to become my new go-to. I loved everything about these frosted fudge brownies.

Homemade Cosmic Brownies topped with mini M&M's

I created this fudge brownie base by adapting my two favorite brownie bases, Fudgy Nutella Brownies and The Ultimate Fudgy Caramel Brownies. I’d like to make all three at once and do side-by-side comparisons, and I’ll get to that right after I budget in money for a new pants wardrobe.

Both of my previous brownie bases use melted butter and a whisk, so they come together in minutes in one bowl, without needing a mixer. From there, I took my favorite things from each recipe — such as a 9×9-inch pan and using both brown and granulated sugars from Fudgy Nutella; and two eggs, cocoa powder, and espresso powder from The Ultimate.

These Little Debbie brownies are dark, dense, rich, the edges are just a bit chewy, with a moist and ultra fudgy interior. There’s zero traces of cakiness and the fudge factor reigns supreme.

As the ganache sets up, it remains soft and firms up just enough to not make a total mess when slicing the brownies. I hate it when the top layer of chocolate cracks, and this isn’t that kind of chocolate.

Upon biting into a dense yet chewy brownie, soft ganache squishes and almost squirts between your teeth. And there’s chewy, ganache-softened M&M’s. It’s the best texture party ever. Ever.

I may be biased, but these are way better than regular Cosmic Brownies. And quite possibly, they’re the best brownies I’ve ever had.

Homemade Cosmic Brownies surrounded by mini M&M's

What’s in Cosmic Brownies? 

To make these frosted fudge brownies, you’ll need: 

  • Unsalted butter
  • Eggs
  • Granulated sugar
  • Brown sugar
  • Brewed coffee
  • Vanilla extract
  • Unsweetened cocoa powder
  • Instant espresso granules  
  • All-purpose flour
  • Semi-sweet chocolate chips
  • Half and half
  • Mini M&M’s

stack of three Little Debbie Cosmic Brownies

How to Make Cosmic Brownies

To make these homemade Cosmic Brownies, you’ll first need to melt the butter. Then, stir in the wet ingredients, followed by the dry. 

Turn the batter into a greased 9×9-inch pan and bake until the top has just set, isn’t jiggly in the center, and a toothpick inserted in the center comes out clean or with a few fudgy moist crumbs, but no batter.

Let the brownies cool completely, then make the chocolate ganache frosting. Smooth the ganache over the brownies, then sprinkle with M&M’s. 

You’ll need to pop these Little Debbie brownies into the fridge to set before you can slice and serve them. 

homemade little debbie brownies

Can I Omit the Coffee? 

The coffee and instant espresso don’t make these Cosmic Brownies taste at all like coffee. They just enhance the rich chocolate flavor and make these brownies even better. But if you don’t have coffee or instant espresso granules on hand, you can just add water. 

Can I Make These in an 8×8-Inch Pan? 

Yes, but since the brownies will be even thicker you’ll need to bake them for longer (I’m not sure how much longer, but likely at least 5 minutes more). 

stack of three Homemade Cosmic Brownies

Can I Add Mix-Ins to These Brownies? 

You probably can, although then you wouldn’t be making authentic Cosmic Brownies. But I imagine chocolate chips, chopped candy bars, or chopped nuts would work in these fudge brownies. 

Can I Use Regular Sized M&M’s? 

Technically, yes, but I think those would be tough to bite down on. Get your hands on mini M&M’s, if possible. 

Homemade Cosmic Brownies topped with mini M&M's

Can I Omit the Frosting? 

If you prefer regular fudge brownies, sure! But if you want real Cosmic Brownies, the frosting is a must. 

Do I Have to Use Half and Half in the Frosting? 

Yes, half and half or heavy cream is a must. If you use regular milk, the ganache will be far too runny and won’t set. 

Homemade Cosmic Brownie

How to Store Cosmic Brownies 

Brownies will keep airtight for 1 week at room temperature, for 2 weeks in the refrigerator, and for up to 6 months in the freezer. I highly recommend storing them in the refrigerator because having a slight chill to brownies this rich and fudgy is almost imperative.

stack of three homemade little debbie brownies

Tips for Making Cosmic Brownies

I love this Cosmic Brownies recipe and don’t want to change a thing, but in order to make them more authentic, use natural unsweetened cocoa powder rather than Hershey’s Special Dark Cocoa Powder, and increase the flour by about 1/4 cup. Cosmic Brownies aren’t as dark and are slightly more cakey, but I prefer darker and fudgier brownies to lighter and cakier.

Baking them in a 9×9-inch pan was my preference, but if you want brownies closer to the real deal, use a 9×13 pan. I don’t like brownies that are on the thin side.

The ganache layer is a bit thicker and when it comes to chocolate, thicker and more is better in my book, but use less if you wish.

I used more M&M’s minis than you’d find on Cosmic Brownies because skimpy isn’t an option. Note that when using M&M’s, they fade. The same thing happened when I made this Frozen Chocolate Pudding and Wafer Cake. The color starts leeching out as they sit on top of chocolate or post-refrigeration when coming back up to room temp. Not a huge deal, but something to mention.

The benefit is that as they sit on the ganache, they soften a bit and become chewy rather than crunchy. The texture of chewy M&M’s is just fabulous and is like nothing I’ve ever had, which more than makes up for their slightly muted color.

Homemade Little Debbie Cosmic Brownies - If you've never had a Cosmic Brownie, change that asap! If you have, then you know how dangerously good it is to be able to make them at home!

Homemade Little Debbie Cosmic Brownies
Yield: 9 brownies

Homemade Little Debbie Cosmic Brownies

Prep Time 10 minutes
Cook Time 25 minutes
Total Time 35 minutes

These homemade Cosmic Brownies are dark, dense, and rich. The edges are just a bit chewy, with a moist and ultra-fudgy interior.


For the Brownies

  • 3/4 cup unsalted butter (1 1/2 sticks), melted
  • 2 large eggs
  • 1 cup granulated sugar
  • 2/3 cup light brown sugar, packed
  • 2 tablespoons coffee or water (coffee leftover from the morning brew is fine)
  • 2 teaspoons vanilla extract
  • 3/4 cup unsweetened natural cocoa powder or dark cocoa powder (I used Hershey’s Special Dark)
  • 1 teaspoon instant espresso granules (make sure it’s instant so it dissolves), optional but recommended
  • 3/4 cup all-purpose flour

For the Ganache

  • 1 1/2 cups semi-sweet chocolate chips
  • 1/2 cup half-and-half or cream (I used half-and-half)
  • 1 cup M&M minis (they’re sold in small tubes and I used 1 1/2 tubes; regular size M&Ms may be substituted)


    Make the Brownies

    1. Preheat oven to 350F. Line a 9-by-9-inch baking pan with aluminum foil, spray with cooking spray; set aside.
    2. In a large, microwave safe bowl, melt the butter, about 90 seconds on high power.
    3. Add the eggs, sugars, coffee, vanilla, and whisk to combine.
    4. Add the cocoa powder, instant espresso, and whisk until incorporated, free from lumps, and smooth. It could take a few minutes if your cocoa powder is lumpy.
    5. Add the flour and stir until it’s just incorporated; don’t overmix.
    6. Turn batter out into prepared pan, smoothing the top lightly with a spatula. Bake for 25 to 29 minutes, or until top has just set, isn’t jiggly in the center, and a toothpick inserted in the center comes out clean or with a few fudgy moist crumbs, but no batter. I baked mine for 26 minutes.
    7. Allow brownies to cool completely in pan. While brownies cool, make the ganache.

    Make the Ganache

    1. Add chocolate chips to a medium, microwave-safe bowl and heat on high power for 1 minute to soften chips. They won’t be melted, this is okay. Don’t stir; set bowl aside.
    2. Heat cream in a glass measuring cup or microwave-safe bowl until it begins to bubble and show signs of just beginning to boiling, about 1 minute on high power.
    3. Pour cream over chocolate chips and let stand for 5 to 10 minutes.
    4. With a whisk, beat mixture until silky, smooth, and combined. If your mixture isn’t smoothing out, heat in 15-second bursts in the microwaves until it can be stirred smooth.
    5. Pour ganache over mostly cooled brownies (after about 30 minutes is fine; they don’t have to be completely cooled). Smooth ganache lightly with a spatula or offset knife.
    6. Evenly sprinkle with M&Ms.
    7. Cover pan with a sheet of foil to prevent fridge smells, and place pan in refrigerator until ganache sets up before slicing and serving, at least 2 hours. Do not slice into them until the ganache has set; feel free to make these in advance and store them in the fridge; they get better with time.


  • Brownies will keep airtight for 1 week at room temperature, for 2 weeks in the refrigerator, and for up to 6 months in the freezer. I highly recommend storing them in the refrigerator because having a slight chill to brownies this rich and fudgy is almost imperative.

Nutrition Information:



Serving Size:


Amount Per Serving: Calories: 640Total Fat: 33gSaturated Fat: 20gTrans Fat: 0gUnsaturated Fat: 11gCholesterol: 94mgSodium: 50mgCarbohydrates: 84gFiber: 4gSugar: 67gProtein: 7g

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