Monster Brownies

This post may contain affiliate links. Read my disclosure policy.

Monster Brownies have everything you’re craving! Crunchy peanuts, M&M candies, and melty chocolate and peanut butter chips all in a chewy fudge brownie!

This recipe takes all the best parts of Monster Cookies and wraps them in a Classic Chocolate Brownie! When you can’t decide what kind of brownie flavor you are craving, the answer is these kitchen sink Monster Brownies.

Monster Brownies in stack


Monster Cookies are the genius idea to make a super cookie mash up of Peanut Butter Cookies, Oatmeal Cookies, and Chocolate Chip Cookies. Naturally the only thing to make this idea even better is to turn Monster Cookies into chocolatey fudge brownies!

If you have already glanced at the recipe card, you may notice there are no oats in this Monster Brownie recipe. Adding rolled oats won’t give you any “oatmeal cookie” flavor in a chocolate brownie batter and only makes them dry. After a lot of testing, the best Monster Brownie recipe had no oats. If you really want the oatmeal cookie flavor, check out the variations below to find out how to work it in!

Speaking of reading ahead to the recipe card, that is definitely a pro tip for any home baker or professional chef. Always read a recipe at least twice through before you start. This not only makes sure you have all your ingredients but also technical steps don’t comes as a surprise.

For these delicious Monster Brownies there aren’t any fancy steps and you can even make them by hand. Since you are using melted butter, you just need a whisk and a large bowl to make these brownies. Easy one bowl, one pan, and loaded with your favorite mix-ins, can these Monster Brownies be any more perfect?

Every bite of Monster Brownies is a variety of flavors and textures. The peanuts and M&M candy shell add crunchy plus the salt from the peanuts balances out some of the sweetness. Then there is the melty chocolate chips, peanut butter chips, and even the M&M chocolate center gets slightly melted. It’s the best medley of salty, sweet, and creamy!

These tasty Monster Brownies are great just as they are but you can always use the mix-ins you have on hand! That’s what makes kitchen sink brownies like this one the best recipes. And of course brownies only get better with a big scoop of Vanilla Ice Cream or drizzle of Chocolate Ganache.


Monster Brownies in baking dish

Save Recipes
Create An Account & Save Recipes


  • Blondies: To make these into Monster Blondies, use brown sugar instead of white sugar, omit the cocoa powder and use 1 ½ cups flour.
  • M&Ms: Use other M&Ms flavors in this Monster Brownie recipe. Try out mini M&Ms, peanut butter M&Ms, or white chocolate M&Ms (while they still have them).
  • Mix-Ins: Swap out the mix-ins for what you have on hand. Try Reese Pieces for M&Ms, walnuts for peanuts, or dark chocolate and white chocolate chips for semi-sweet chocolate chips.
  • Peanut Butter: Add a ¼ cup peanut butter to your brownie batter for even more peanut butter flavor! Nutella would taste great too and make your brownies really rich.
  • Oatmeal Cookie: For that oatmeal cookie taste, fold in crushed hard oatmeal cookies or granola clusters. Don’t use rolled oats or quick oats in your batter, it will make the brownies dry.



  • Serve: Monster Brownies can be kept at room temperature for up to 3 days. Cover baking pan tightly with aluminum foil or plastic wrap.
  • Store: Refrigerate Monster Brownies in an airtight container or plastic storage bag for up to 1 week. Warm in the microwave or bring to room temperature to serve.
  • Freeze: Cool your Monster Brownies completely before storing in a freezer safe bag. Defrost brownies overnight in the refrigerator or on the counter before serving.

Monster Brownies in stack, top-down view

Pin This

Like this recipe? Save it to your Pinterest board now!




Monster Brownies

5 from 3 votes
  • Yield: 16
  • Prep Time: 10 minutes
  • Cook Time: 30 minutes
  • Total Time: 40 minutes
  • Course: Dessert
  • Cuisine: American
  • Author: Sabrina Snyder

Monster Brownies have everything you're craving! Crunchy peanuts, M&M candies, and melty chocolate and peanut butter chips all in a chewy fudge brownie!


  • 1/2 cup unsalted butter , melted
  • 1 cup sugar
  • 2 large eggs
  • 2 teaspoons vanilla extract
  • 1/3 cup unsweetened cocoa powder
  • 1/2 cup flour
  • 1/4 teaspoon salt
  • 1/4 teaspoon baking powder
  • 1/2 cup M&M candies , divided
  • 1/2 cup salted peanuts , divided
  • 1/2 cup peanut butter chips
  • 1/2 cup semi-sweet chocolate chips


Note: click on times in the instructions to start a kitchen timer while cooking.

  1. Preheat oven to 350 degrees.
  2. Spray an 8x8 inch baking pan with baking spray.
  3. Whisk together melted butter, sugar, eggs, and vanilla extract.
  4. Whisk in the cocoa powder, flour, salt, and baking powder.
  5. Fold in chocolate chips, peanut butter chips, and half the M&M candies and peanuts.
  6. Spread batter evenly into greased baking pan.
  7. Sprinkle the remaining ¼ cup M&Ms and peanuts over the batter.
  8. Bake for 25 to 30 minutes.

Nutrition Information

Yield: 16 , Amount per serving: 247 calories, Calories: 247g, Carbohydrates: 28g, Protein: 5g, Fat: 14g, Saturated Fat: 8g, Cholesterol: 38mg, Sodium: 81mg, Potassium: 113mg, Fiber: 2g, Sugar: 21g, Vitamin A: 222g, Calcium: 25g, Iron: 1g

All images and text © for Dinner, then Dessert.

Keyword: Monster Brownies

Monster Brownies collage

Leave a comment & rating

Your email address will not be published. Required fields are marked *

Recipe Rating

This site uses Akismet to reduce spam. Learn how your comment data is processed.