Monster Cookie Fudgy Brownies Recipe

If you’ve ever found yourself torn between a gooey brownie and a chunky, peanut buttery monster cookie, the Monster Cookie Fudgy Brownies are your match made in dessert heaven! Imagine thick, fudgy brownie layers swirled with bursts of creamy peanut butter, oats, chocolate chips, and those irresistible, colorful mini M&M’s—all baked into one glorious bar. This playful, over-the-top treat is the ultimate answer to an afternoon sweet tooth, weekend baking adventure, or a pick-me-up any day of the week.

Ingredients You’ll Need

Every component in Monster Cookie Fudgy Brownies brings its own magic, from the rich depth of cocoa powder to the unforgettable chew of quick oats. You’ll recognize just about everything here—classic pantry staples working together to create one seriously fun and decadent dessert!

• White granulated sugar: Sweetens both the brownie and cookie layers, giving the brownies their classic crackly top.
• Large eggs + egg yolk: These add richness and fudginess; the extra yolk keeps the brownies extra moist.
• Unsalted butter: Adds buttery flavor and tenderness throughout both batters.
• Oil (canola or vegetable): Ensures the brownies stay ultra-fudgy and moist, even after cooling.
• Pure vanilla extract: A key to adding warmth and enhancing all those chocolate and peanut butter flavors.
• All-purpose flour: Provides the structure—measured carefully so your brownies are chewy, not cakey.
• Unsweetened cocoa powder (dutch process): Brings the deep, chocolatey goodness that makes the brownies sing.
• Cornstarch: Keeps both layers incredibly soft and lends a melt-in-your-mouth feel.
• Salt: Just a touch amplifies all the sweet and chocolatey flavors.
• Semi-sweet chocolate chips: Give pools of melted chocolate in every fudgy bite.
• Milk chocolate chips: Add creamy chocolate notes to balance out the cookie crunch.
• Baking soda & baking powder: Help the cookie layer puff up just a bit, so you get tender and chewy all at once.
• Brown sugar (packed light or dark): Adds moisture and a hint of toffee flavor to the monster cookie dough.
• Peanut butter (creamy): Brings that unmistakable monster cookie flavor and creamy bite.
• Quick oats: For hearty chew and texture in the cookie layer.
• Mini chocolate chips: Stud every bar with extra chocolate in every bite!
• Mini M&M’s: The colorful signature of monster cookies—these add crunch and fun.

How to Make Monster Cookie Fudgy Brownies

Step 1: Prepare the Monster Cookie Dough

Start by whisking together the flour, cornstarch, baking soda, baking powder, and salt in a bowl—this little mix makes sure your cookie layer bakes up perfectly tender and chewy, never tough. In another bowl, beat the butter, brown sugar, and white sugar until they turn pale and fluffy (about a minute or so), then mix in the peanut butter for pure, creamy goodness. Add the vanilla and egg, scrape down the bowl, and blend until everything’s well mixed. Now, gently mix in the dry ingredients just until combined, then stir in the oats, mini M&M’s, and chocolate chips. Cover the dough and let it chill in the fridge for about 40 minutes; this step is crucial for scoopable dough that holds its shape during baking.

Step 2: Make the Fudgy Brownie Batter

While your cookie dough chills, preheat the oven to 325°F. Prepare a 9×9-inch pan by spraying it with nonstick spray and lining with parchment paper (leave an overhang for easy removal!). In a clean bowl, whisk together flour, cocoa powder, cornstarch, and salt. In your mixer, whip the granulated sugar, eggs, and extra yolk for a full five minutes—trust me, this aeration gives your brownies an irresistible fudgy-yet-light texture. While that’s mixing, melt the butter and let it cool slightly. Now blend the melted butter, oil, and vanilla into the egg mixture, then switch to a spatula to gently fold in the dry ingredients, taking care to keep all that lovely air in the batter. Add both kinds of chocolate chips, and you’re ready to bake!

Step 3: Layer and Bake

Pour the brownie batter into your prepped pan and gently spread it to the corners. Bake for 15 minutes so the brownie layer just begins to set up—this allows the cookie topping to bake to chewy perfection without sinking in. As soon as the timer dings, grab your monster cookie dough from the fridge. Take small handfuls, lightly flatten into discs, and arrange them over the partially baked brownie layer. Continue until all the cookie dough is used up and the top is covered in generous cookie patches.

Step 4: Finish Baking

Pop the pan back in the oven and bake for another 20 minutes. To keep that gorgeous monster cookie top from over-browning, lay a piece of foil loosely over the pan, then bake for another 5-10 minutes. You’re looking for a set top without any jiggle in the center—a little patience here pays off with perfect texture. Transfer to a cooling rack and let the Monster Cookie Fudgy Brownies cool completely in the pan before lifting out and slicing. If you can resist cutting in too soon, you’ll be rewarded with those neatly layered, gooey squares!

Step 5: Slice and Enjoy

Once cool, lift the slab from the pan using the parchment paper overhang. Grab your sharpest knife and slice into big, bakery-style squares. Admire those pockets of chocolate, streaks of peanut butter, and cheerful M&M pops. All that’s left is to savor every bite!

How to Serve Monster Cookie Fudgy Brownies

Garnishes

For an extra flourish, sprinkle a few more mini M&M’s or chocolate chips over the brownies while they’re still just barely warm, so they nestle into the top. A light dusting of flaky salt or a drizzle of warm peanut butter can push these Monster Cookie Fudgy Brownies right over the edge into dessert stardom!

Side Dishes

Want to make your brownie moment even sweeter? Serve with a scoop of vanilla ice cream, a big glass of cold milk, or—my favorite—a creamy coffee or hot chocolate. The richness of the brownies is perfectly balanced by something cold and creamy on the side.

Creative Ways to Present

For parties or bake sales, cut the brownies into mini squares and stack them on a platter, or skewer them with colorful toothpicks. For a fun, over-the-top presentation, layer your Monster Cookie Fudgy Brownies in a trifle bowl with whipped cream and more M&M’s. They also make unforgettable brownie sundaes or lunchbox treats!

Make Ahead and Storage

Storing Leftovers

Leftover Monster Cookie Fudgy Brownies can be stored in an airtight container at room temperature for up to four days. In fact, some say they get even fudgier after the first day, as all the flavors mingle and meld together!

Freezing

These brownies freeze beautifully. Simply wrap individual squares tightly in plastic wrap, then store in a freezer bag or container for up to two months. When your brownie cravings strike, just grab and go!

Reheating

For maximum gooeyness, reheat a brownie square in the microwave for 10-15 seconds. This brings the chocolate and peanut butter back to melty perfection—especially wonderful if you’re serving with ice cream!

FAQs

Can I use natural peanut butter instead of regular creamy?

It’s best to stick with no-stir, creamy peanut butter for Monster Cookie Fudgy Brownies. Natural varieties tend to separate and can make the dough greasy or dry.

Do I have to chill the monster cookie dough?

Yes, chilling is crucial! It helps the dough firm up so it doesn’t spread too much in the oven, giving you that signature chewy, chunky monster cookie texture on top of your brownies.

What if I don’t have Dutch process cocoa powder?

You can use regular unsweetened cocoa powder in a pinch, but Dutch process gives a deeper, richer chocolate flavor for your brownies. The result will still be delicious either way!

Can I make Monster Cookie Fudgy Brownies gluten-free?

Absolutely! Swap the all-purpose flour for a high-quality 1:1 gluten-free baking blend and use certified gluten-free oats. The brownies will still turn out perfectly indulgent.

How do I know when the brownies are done baking?

The edges should look set and the center should no longer jiggle when you gently shake the pan. If you insert a toothpick, it should come out with a few moist crumbs, not raw batter.

Final Thoughts

If you’re ready to wow your family, friends, or—let’s be honest—just yourself, bake up a batch of Monster Cookie Fudgy Brownies. With their bright pops of color, rich chocolate base, and monster cookie topping, these brownies are the kind of treat everyone remembers. Give them a try and get ready for some serious swooning!

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