Monster Cookie Brownies

These Monster Cookie Brownies combine rich, thick, fudgy chocolate brownies with a buttery oatmeal monster cookie crumble loaded with colorful M&M’s. Made from scratch with Dutch cocoa powder, chocolate chips, and a golden cookie topping, these brownie cookie bars give you the best of both worlds in every bite! This easy recipe makes 16 delicious brownies in an 8×8-inch pan, perfect for parties, potlucks, bake sales, or satisfying that chocolate craving.

I think even Cookie Monster himself would have a hard time choosing between cookies and brownies. And who could blame him? Thankfully, with these Monster Cookie Brownies, there’s no need to choose! C is for cookie, B is for brownie, and both are pretty darn delicious!

What makes these brownies extra special is the contrast in textures. The bottom layer is dense, rich, and wonderfully fudgy, while the oatmeal cookie topping is buttery, sweet, and slightly crumbly. Add those colorful little pops of M&M’s, and you’ve got one fun dessert that’s just as delicious as it is pretty!

And while they’re fun for birthdays and holidays (just swap out the M&M’s colors!), these homemade brownies are way too good to save for a special occasion. Sometimes a regular Tuesday is reason enough to bake a batch!

Why You’ll Love These Monster Cookie Brownies

• Two desserts in one: Homemade brownies and monster cookies come together in every delicious bite.
• Rich and fudgy: Dutch cocoa powder and chocolate chips create a thick, chocolatey brownie layer.
• Buttery cookie crumble: The oatmeal cookie topping adds a sweet, crumbly texture that pairs perfectly with the fudgy brownies.
• Loaded with M&M’s: Colorful candy-coated chocolates add little pops of chocolate and crunch.
• Easy to make: Both layers use simple pantry ingredients, and everything comes together in one baking pan.
• Perfect for sharing: One 8×8-inch pan makes 16 brownie cookie bars, perfect for parties, potlucks, and bake sales.

Ingredients in Monster Cookie Brownies

These homemade monster cookie brownies are made with two delicious layers. Most of the ingredients are probably already in your kitchen! You’ll find the exact measurements in the printable recipe card below.

For the Brownie Layer:

• Salted butter: Adds richness and moisture to the brownies.
• Granulated sugar: Sweetens the brownie batter and helps create that classic fudgy texture.
• Egg and egg yolks: Using one whole egg and two additional yolks keeps the brownies rich and fudgy rather than cakey.
• All-purpose flour: Gives the brownies structure without making them too dense.
• Dutch cocoa powder: Creates a deep, dark chocolate flavor. Regular unsweetened cocoa powder works, too.
• Semi-sweet chocolate chips: Add even more chocolate goodness to the brownie layer.

For the Monster Cookie Topping:

• Salted butter: Softened butter creates the base for the buttery cookie dough.
• Light brown sugar: Adds moisture, sweetness, and a hint of caramel flavor.
• Granulated sugar: Works with the brown sugar to give the cookie topping its texture.
• Egg: Helps hold the monster cookie dough together.
• All-purpose flour: Gives the cookie topping structure.
• Old-fashioned oats: Add that classic oatmeal cookie texture that makes monster cookies so delicious.
• M&M’s: These colorful candy-coated chocolates are a signature part of monster cookies and add a little chocolate crunch to every bite.

How to Make Monster Cookie Brownies

Making these monster cookie dough brownies is easier than you might think! The brownie layer gets a little head start in the oven before the monster cookie topping is added. This helps create those beautiful, distinct layers.

Preheat your oven to 350°F. Grease an 8×8-inch baking pan with butter or nonstick cooking spray.

Melt the butter in the microwave. Whisk in the granulated sugar, followed by the whole egg and egg yolks. Add the flour and Dutch cocoa powder, whisking until combined. Fold in the chocolate chips.

Spread the brownie batter evenly into the prepared pan and bake for 10 minutes. The brownies will still be underbaked at this point, which is exactly what we want.

While the brownies are in the oven, cream the softened butter, brown sugar, and granulated sugar together with an electric mixer. Mix in the egg, followed by the flour and oats, until no dry pockets remain.

Fold the candies into the cookie dough until evenly distributed. The dough will look a little dry and crumbly, almost like a streusel topping. That’s normal!

Sprinkle chunks of monster cookie dough evenly over the partially baked brownie layer.

Return the pan to the oven and bake for another 10 minutes, or until the cookie topping is golden brown. Allow the brownies to cool in the pan for about 30 minutes before slicing into 16 squares.

How to Store Monster Cookie Brownies

At room temperature: Store completely cooled brownies in an airtight container on the counter for up to 5 days. Make sure they’re completely cool before sealing the container to prevent moisture from building up inside.

To reheat: If you love a warm, fudgy brownie, pop one in the microwave for about 15 seconds, or until warmed through.

To freeze: Wrap individual cooled brownies tightly and place them in a freezer-safe container for up to 3 months. Thaw at room temperature before enjoying.

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If you can’t wait to try this recipe for Monster Cookie Brownies, make sure you can find it! Pin it to your favorite Pinterest recipe board before you go!

Tips for the Best Monster Cookie Brownies

Best Monster Cookie Brownies Tip: Don’t skip that first baking step! Partially baking the brownie batter before adding the monster cookie dough helps keep the cookie topping from sinking into the chocolate layer. That’s how you get those beautiful layers in every square.

• Don’t overmix the brownie batter. Mix just until the dry ingredients are incorporated to help keep the brownies tender and fudgy.
• Use softened butter for the cookie dough. This makes it easier to cream with the sugars and creates a better cookie topping.
• Expect crumbly cookie dough. Unlike traditional scoop-and-bake cookies, this dough is meant to be a little dry. It should resemble a chunky streusel topping.
• Let the brownies cool before cutting. Giving them about 30 minutes to cool in the pan helps the layers set and makes slicing easier.
• Use your favorite chocolate chips. Semi-sweet chocolate balances the sweetness of the cookie topping, but milk chocolate or dark chocolate chips work, too.
• Change the M&M’s for the occasion. Regular M&M’s make these brownies perfect year-round, but you can use seasonal colors for Halloween, Christmas, Valentine’s Day, or birthday parties.

Monster Cookie Brownies FAQs

• What are monster cookie brownies? Monster cookie brownies combine a rich, fudgy chocolate brownie base with a topping inspired by classic monster cookies. The oatmeal cookie dough and colorful M&M’s give them that familiar monster cookie flavor, while the brownie layer adds plenty of chocolate.
• Can I use quick oats instead of old-fashioned oats? Yes! Old-fashioned oats give the cookie topping a heartier, chewier texture, while quick oats create a finer texture. Both will work.
• Can I use regular cocoa powder instead of Dutch cocoa? Absolutely. Dutch cocoa powder gives the brownies a darker color and richer chocolate flavor, but regular unsweetened cocoa powder can be substituted.
• Can I use unsalted butter? Yes. If you’re using unsalted butter, add approximately ¼ teaspoon of salt to the brownie batter and another ¼ teaspoon to the monster cookie dough.
• Why does the brownie recipe use extra egg yolks? The additional egg yolks help create a rich, fudgy texture. Using three whole eggs instead would add extra egg whites and change the consistency, making the brownies more cake-like.
• Why do I bake the brownies before adding the cookie dough? The brownie batter needs a little time to set before adding the topping. Otherwise, the heavier cookie dough could sink into the brownie layer instead of staying on top.
• Can I make these brownies ahead of time? Yes! These brownies are a great make-ahead dessert. Bake them the day before your gathering, allow them to cool completely, and store them in an airtight container until you’re ready to serve.

More Brownie, Cookie and Bar Recipes to Love

If you love these Monster Cookie Brownies, I’ve got plenty more sweet treats for you to try! From rich, fudgy brownies to chewy homemade cookies and easy dessert bars, there’s something here for every sweet tooth!

• Pecan Brownies: Rich, fudgy chocolate brownies loaded with melty chocolate chips and crunchy pecans. A chocolate lover’s dream!
• Sweet and Salty Brownies: (pictured above) Fudgy dark chocolate brownies topped with crunchy pretzels, potato chips, and a sprinkle of sea salt. The perfect sweet and salty combination!
• Seven Layer Cookies: These old-fashioned magic cookie bars are layered with graham cracker crumbs, chocolate, butterscotch, coconut, and pecans. So easy and so good!
• PB&J Oatmeal Cookie Bars: Peanut butter oatmeal cookie bars swirled with sweet grape jelly. All the flavors of your favorite childhood sandwich baked into one delicious treat!
• Grandma Jane’s Oatmeal Raisin Cookies: Soft, chewy oatmeal cookies filled with sweet raisins. This tried-and-true family recipe has been a favorite for generations!
• Chocolate Mint Oreo Cookies: Rich, fudgy chocolate cookies packed with crunchy mint Oreos and melty Andes mints. A chocolate and mint lover’s dream!

Still looking for something sweet? Browse all of my Dessert Bar Recipes for even more brownies, cookie bars, and easy homemade treats!

There’s something pretty wonderful about a dessert that combines two favorites into one. These Monster Cookie Brownies have everything you love about a fudgy homemade brownie, plus a buttery oatmeal cookie topping filled with colorful M&M’s.

Serve them with a cold glass of milk, add a scoop of vanilla ice cream, or enjoy one straight from the pan. However you serve them, I have a feeling these brownies won’t last long!

If you make this Monster Cookie Brownies recipe, I’d love to hear what you think! Leave a comment and a star rating below, and don’t forget to share your creations with me!