Monster Cookie Fudgy Brownies are what happens when two favorites—the classic monster cookie and irresistibly rich brownies—join forces in one pan. Imagine the gooiest, chocolate-packed brownies you’ve ever tried, swirled with a cheerful monster cookie dough brimming with peanut butter, oats, mini M&M’s, and melty chocolate chips. Every bite is dense, chewy, colorful, and packed with childhood nostalgia. If you’ve been searching for the ultimate treat that satisfies every craving, these Monster Cookie Fudgy Brownies are the answer.

Monster Cookie Fudgy Brownies Recipe - Recipe Image

Ingredients You’ll Need

You’ll be excited by how common, yet essential, these ingredients are—the magic happens when you combine them in just the right way. Every scoop and sprinkle plays a role in delivering that crave-worthy richness, chew, and playful color that make Monster Cookie Fudgy Brownies so special.

White granulated sugar: Sweetens the brownies and gives them that classic crackly top.
Large eggs & egg yolk: Eggs provide structure; the extra yolk amps up the fudgy texture.
Unsalted butter: Creates richness and depth, while unsalted lets you control the sodium.
Oil (canola or vegetable): Adds extra moisture for gooey-soft brownies.
Pure vanilla extract: Rounds out all the chocolate and peanut butter flavors.
All-purpose flour: Gives both the brownies and monster cookie dough their shape.
Unsweetened cocoa powder (dutch process): Intensifies the chocolatey goodness with a richer flavor.
Cornstarch: Keeps brownies soft, and helps the cookie dough stay thick and chewy.
Salt: Raises every flavor note and keeps the bars from tasting flat.
Semi-sweet chocolate chips: Melty pockets of chocolate folded into the brownies.
Milk chocolate chips: A sweeter contrast to the semi-sweet, creating layers of flavor.
Baking soda & baking powder: Helps the monster cookie dough rise and stay tender.
Brown sugar: Deepens the cookie dough with caramel-like notes and extra moisture.
Peanut butter (creamy): A true monster cookie essential, giving richness and warmth.
Quick oats: Adds chewiness and a hearty texture to the cookie dough layer.
Mini chocolate chips: Ensures chocolate in every bite of the monster cookie dough.
Mini M&M’s: Adds color, crunch, and that iconic monster cookie look that’s so 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 medium bowl. In a separate large bowl, beat together the room temperature butter, brown sugar, and white sugar for about a minute—aim for light, airy, and fluffy. Blend in the peanut butter, mixing for another minute until creamy. Next, add the vanilla extract and egg, then mix again, scraping the bowl as needed to make sure everything is totally incorporated. Gradually add the dry ingredients to the wet, mixing until just combined. Fold in the quick oats, mini M&M’s, and mini chocolate chips. Pop this dough in the fridge to chill for at least 40 minutes, which keeps the cookies thick and prevents spreading later.

Step 2: Make the Fudgy Brownie Batter

In a fresh bowl, beat together the granulated sugar, eggs, and extra yolk until pale and slightly thick—it should take about two minutes. Melt the butter (microwave or stovetop works) and stir it in, followed by the oil and vanilla extract. In another small bowl, sift together the flour, cocoa powder, cornstarch, and salt. Add these dry ingredients to your wet mix, stirring until no dry streaks remain, then gently fold in both the semi-sweet and milk chocolate chips. This batter will be glossy, thick, and deeply chocolatey.

Step 3: Assemble the Monster Cookie Fudgy Brownies

Line a baking pan with parchment paper or grease it lightly. Pour the brownie batter in first and smooth it out. Using a spoon or cookie scoop, gently drop balls of chilled monster cookie dough all over the brownie layer—don’t worry about being perfect! Use a knife or skewer to swirl them together slightly so each piece has a combination of fudgy brownie and monster cookie bites. Scatter a few extra mini M&M’s or chocolate chips on top for a bakery-style finish.

Step 4: Bake and Cool

Bake the assembled pan in a preheated oven at 350°F (175°C) for about 28-32 minutes. The brownies should be set around the edges but still have a gentle jiggle in the center—this is what keeps them that magical level of fudgy. Let the Monster Cookie Fudgy Brownies cool in the pan for at least 45 minutes before lifting out and slicing. If you like super tidy squares, a little time in the fridge does wonders.

Step 5: Slice and Enjoy

Use a sharp knife to cut the brownies into squares. Wipe the knife between cuts for the cleanest edges. Serve at room temperature for the ultimate chewy, creamy effect, or slightly warmed for maximum meltiness. Each square is a celebration of all things chocolatey, peanut buttery, and fun!

How to Serve Monster Cookie Fudgy Brownies

Garnishes

Go all out with toppings—press in a few extra mini M&M’s or drizzle on a bit of melted peanut butter for instant wow factor. Another great option is a light dusting of powdered sugar or a scoop of vanilla ice cream. For special occasions, a swirl of whipped cream and extra sprinkles brings out the playful monster cookie vibe!

Side Dishes

As indulgent as these brownies are, they play nicely with fresh fruit, a scoop of tangy Greek yogurt, or even a glass of cold milk. If you’re feeling decadent, serve alongside a milkshake or warm mug of hot chocolate—the rich flavors in Monster Cookie Fudgy Brownies were made for sharing.

Creative Ways to Present

Try stacking brownie squares into towers on a colorful platter, or cut them into fun shapes using cookie cutters for parties. For a DIY dessert bar, set out bowls of toppings so everyone can customize their own monster cookie brownie. These are also amazing layered into trifles with whipped cream and crushed cookies!

Make Ahead and Storage

Storing Leftovers

Monster Cookie Fudgy Brownies will stay moist and chewy for several days when stored in an airtight container at room temperature. Separate layers with parchment to keep the tops pretty and to prevent sticking. You can also keep them in the fridge if your kitchen runs warm—they’ll be extra dense and fudgy straight from the fridge.

Freezing

Yes, you can freeze these! Place cooled, cut brownies in a single layer on a tray, freeze until solid, then store in an airtight bag or container with parchment between layers. They keep beautifully for up to 2 months—just thaw at room temp or even eat them cold for an extra chewy treat.

Reheating

If you love that fresh-baked softness, microwave individual brownie squares for 8-10 seconds or warm tray portions in a low oven (300°F/150°C) for a few minutes. Just enough heat will revive the chocolate chips and make those monster cookie swirls extra gooey, without drying the brownies out.

FAQs

Can I use natural peanut butter instead of creamy?

Natural peanut butter tends to be oilier and less stable; for best texture, stick with conventional creamy peanut butter, as it keeps the monster cookie dough thick and tender. If using natural, make sure to stir it very well and be aware the final product may be more crumbly.

Can I make Monster Cookie Fudgy Brownies gluten free?

Absolutely! Swap the all-purpose flour for a high-quality gluten-free blend (make sure it contains xanthan gum) and double-check that your oats are certified gluten free. The taste and texture will still be delicious.

Do I have to chill the monster cookie dough?

Yes! Chilling prevents the cookie dough swirls from over-spreading and ensures those fun chunks of M&M’s and chocolate chips stay distinct and chewy within each square. Don’t skip this step if you want true Monster Cookie Fudgy Brownies texture.

Can I add nuts or swap in other candies?

Go for it! Chopped peanuts, pecans, or even pretzels make for exciting extras. You can swap the M&M’s for Reese’s Pieces, mini peanut butter cups, or your favorite chocolate candies—monster cookies are made for mix-and-match fun.

How do I know when the brownies are done baking?

Peek at the edges: they should look set and just start to pull away from the pan, while the center is slightly underbaked. A toothpick should come out with moist, fudgy crumbs—not totally clean—for perfect Monster Cookie Fudgy Brownies.

Final Thoughts

If you’re ready to wow your friends or just indulge your own dessert dreams, don’t wait to try Monster Cookie Fudgy Brownies. They’re the perfect mashup of nostalgia and pure chocolate bliss—one bite and you’ll see why they’re an instant favorite in any kitchen. Happy baking!

Monster Cookie Fudgy Brownies Recipe

★★★★★

5.2 from 23 reviews

Author: Mariam
Total Time: 50 minutes
Yield: 12 brownies 1x
Diet: Vegetarian

Print Recipe

Description

Indulge in the ultimate decadence with these Monster Cookie Fudgy Brownies! A rich, fudgy brownie base is topped with a layer of irresistible monster cookie dough, creating a treat that’s sure to satisfy all your sweet cravings.

Instructions

Monster Cookies – In a medium-sized mixing bowl, combine flour, cornstarch, baking soda, baking powder, and salt.
Using a mixer, beat butter, brown sugar, and sugar for 1 minute until light and fluffy. Add peanut butter and mix for another minute.
Stir in vanilla and egg until combined. Slowly add dry ingredients, then mix in oats, M&M’s, and chocolate chips. Chill dough for 40 minutes.

Prep Time: 20 minutes
Cook Time: 30 minutes
Category: Dessert
Method: Baking
Cuisine: American