Monster Cookie Brownies (2024)

Monster Cookie Brownies start with a boxed brownie mix and topped with a homemade monster cookie dough, with peanut butter, oats, mini chocolate chips and mini m&m’s candies. A mix between a brownie and a cookie! This easy dessert recipe is always a favorite and so yummy too!

Monster Cookie Brownies Recipe

These easy to make monster cookie brownies combine two of my very favorite things, brownies + monster cookies ♥.

Monster Cookies are an amazing mix of oats, peanut butter, chocolate chips, and m&m’s. The brownie base is just an easy box mix of brownies, you can of course make homemade brownies instead, and then it’s topped off with monster cookie dough that gets baked right in. So you basically have a brownie and a cookie on one bite!

Ingredients You Need

There are several ingredients you need for this recipe, but it’s easy to mix up, and of course the base is a boxed brownie mix and that is quick also! You just need the ingredients called for on the back of the brownie mix.

• Milk Chocolate Brownie Mix – You will need to make the brownies according to the package instructions. It normally calls for eggs, oil, and water.
• Butter
• Creamy Peanut Butter – For best results do not use the all-natural peanut butter. Stick with regular peanut butter like Jif, Skippy, or Peter Pan.
• Sugar
• Brown Sugar – I use light brown sugar for all my baking.
• Large
• Vanilla Extract
• All-Purpose Flour
• Quick Oats
• Baking Soda
• Salt – Regular, iodized table salt is what I use in this recipe. Kosher salt and sea salt will also work fine.
• Mini Chocolate Chips
• Mini M&M’s

How to Make Monster Cookie Brownies

To make this brownie recipe you’ll need two mixing bowls, some measuring cups and spoons, and a hand mixer. You can just mix the cookie dough mixture with a wooden spoon but I find it much easier to use a hand mixer.

Make the Brownies

• Prepare brownies according to the instructions on the back of the box. Do not bake them. Just make the batter and pour it into a 9×13 baking dish that has been sprayed with cooking spray or lined with parchment paper.

Monster Cookie Dough

• In a mixing bowl, with a hand mixer, beat together the softened butter and peanut butter until creamy.
• Add the sugars, egg, and vanilla extract. Mix until combined.
• Add the dry ingredients and mix just until combined.
• Add in the chocolate chips and m&m candies and stir together.

Monster Cookie Brownies

• Pour the brownie batter into the prepared 9×13 baking dish.
• Take some of the cookie dough and smash it into a flat shape (dough will be sticky but try your best) and lay it on top of the brownie batter. Continue on with the remaining cookie dough.
• Bake in the oven and let cool in the pan before cutting. If you cut them while hot, the brownies will fall apart and they won’t hold together well.

Tips For Success

Here are a few of my helpful tips that will hopefully make this recipe a success in your own kitchen.

• Mini Sized : I know some might be tempted to use regular chocolate chips and regular sized m&m’s. Which will work just fine. But, I highly suggest sticking with the mini sized chocolate chips and m&m’s for this recipe. I love the smaller chunks of chocolate throughout the brownie, rather than one big piece of chocolate. I think it also looks prettier with the small m&m’s because there is more of them.
• Peanut Butter : Don’t try to use all-natural peanut butter, it won’t work as well. Stick with regular peanut butter like Jif, Skippy, and Peter Pan. The all-natural peanut butter is much thicker, not as much oils, and therefore it turns baked goods really dry.
• Make It Pretty! : Save some of the mini chocolate chips and mini m&m’s, or just use additional, to sprinkle on top of the bars before baking. I usually just add extra and gently press them into the top of the brownies before baking.
• Tip For Easy Cutting : I love using the pre-cut parchment paper sheets when making brownies and bars. I spray the baking pan with cooking spray and then lay a pre-cut parchment paper sheet in the pan, vertically, so that way the bottom of the pan is covered but there is lots of extra hanging over the sides which makes it easy to pick up the bars when I’m ready to cut them.

How To Store Leftover Brownies

Leftover brownies will keep well, in an air-tight container, at room temperature for 4-5 days. If they last that long!

If you prefer cold brownies then they can also be stored in the fridge as well.

Can I Freeze Monster Cookie Brownies?

Yes you can freeze these monster cookie brownies! Prepare according to directions and let them cool completely to room temperature.

• Cut into squares and wrap each piece in tin foil. Place all the foil wrapped bars into a freezer safe container like a gallon-sized Ziploc bag and freeze for up to 1-2 months.
• You don’t have to wrap the squares of brownie in tin foil but I prefer to do that to avoid the brownies from sticking together as they freeze.
• I have also just put a brownie or two inside a sandwich Ziploc bag and stuck them in the freezer. I usually do this if I know they will be eaten fairly quickly.

Let frozen brownies thaw at room temperature for a little bit before you eat. You can also warm it up in the microwave for a few seconds.

You’ll Love These Monster Cookie Inspired Recipes

• Monster Cookie Energy Balls
• Reese’s Stuffed Monster Cookies
• No Flour Monster Cookie Bars
• Triple Peanut Butter Monster Cookies
• Monster Cookie Dough Cheeseball Dip

More Brownie Recipes to Make

• Easy Nutella Brownies
• Candy Bar Brownies
• Cake Mix Triple Fudge Reese’s Brownies
• Andes Mint Cookie Brownies