Monster Cookies

If you’re looking for a new favorite monster cookie recipe, this is the one! I started with our family’s favorite soft peanut butter cookies and added oats and candies to turn them into these easy monster cookies!

Monster cookie on white background with M&M's scattered

I have been on such a cookie baking kick lately. 

I mean, what’s not to love about butter, sugar, flour, and a whole lot of mix-ins?? 

I’m honestly not sure if I love the cookie dough or the actual baked cookies more, but either way…it’s all cookies, all the time up in this house!

Between these monster cookies and these graham cracker cookies, our cookie jar is always stocked.

monster cookie ingredients in a bowl

How to make this monster cookie recipe:

I start with my soft peanut butter cookies as a base, because it is the all-time best peanut butter cookie recipe. If you haven’t tried it, you must.

Then I just swap out a little flour for some oats and add in some m&m candies. The recipe is so easy to make and best of all, there is no chilling required! The cookies bake up super thick and puffy, even without spending any time in the fridge – love that!

You can use any variety of m&m candies that you like. I normally go for the classic, but the peanut or peanut butter are pretty great too!

a scoop of peanut butter cookie dough with m&m's

Tips for the best cookies:

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Fully cream the butter, peanut butter, and sugar before adding your dry ingredients. The mixture should be light and fluffy!

Use a cookie scoop to get evenly sized portions of dough. This will ensure all your cookies bake evenly (and it helps eliminate your kids fighting for the biggest one – because you know they do that). 

close up cookie on white background

These cookies hold their shape in the oven, so if you want them a bit flatter, go ahead and squish them down a bit with your fingers before baking. As you can see, we like fat balls of cookies in this house!

When the cookies come out of the oven, they will be really soft.  Don’t try to pick them up right away, they will likely just crumble.  I like to put let them cool on my sheet for 5 minutes then transfer them to finish cooling. 

a few cookies piled together

Substitution options:

Feel free to swap in any type of m&m or other small piece of candy you like here. 

Rolled oats can be used in place of quick oats. They’ll just add a heartier texture to the cookies.

Sun Butter should work well in this recipe, if you have peanut allergies. 

More peanut butter favorites:

Peanut butter is one of my favorite foods to eat and bake with.  

Give these chocolate peanut butter no bake cookies a try on days when you don’t want to turn on the oven.

This peanut butter 7 layer bar is so rich and flavorful!

You seriously can’t go wrong with these peanut butter frosted brownies.

My doggies love peanut butter too, so I made them some peanut butter banana dog treats.

peanut butter m&m cookies on white background

a few cookies piled together

Monster Cookies

Prep Time
10 mins
Cook Time
8 mins
Total Time
18 mins
Servings: 30 cookies
Course: Dessert
Cuisine: American
Keyword: back to school, easy cookie recipes, kid-friendly recipes
Calories: 157 kcal

If you're looking for a new favorite monster cookie recipe, this is the one!


  • 1/2 cup butter, softened
  • 1/2 cup peanut butter
  • 3/4 cup brown sugar
  • 1/4 cup sugar
  • 1 large egg
  • 1 teaspoon vanilla
  • 1 1/4 cups flour
  • 1/2 cup quick oats
  • 1 teaspoon baking soda
  • 1/4 teaspoon salt
  • 1 cup m&m candies
  • 1/2 cup milk chocolate chips


  1. Preheat oven to 350 degrees and line a cookie sheet with parchment paper.
  2. In the bowl of a stand mixer, cream together the butter, peanut butter, and sugars until light and fluffy. Beat in the egg and vanilla.

  3. In a medium bowl, combine the flour, oats, baking soda, and salt. Gradually add to the creamed mixture and beat until well combined.
  4. Stir in the m&m candies and chocolate chips.
  5. Drop spoonfuls of dough onto baking sheet 2 inches apart and flatten slightly with the back of a spoon. Bake for 8 minutes exactly.
  6. Let the cookies set on the baking sheet for 5 minutes to set up before transferring to a wire cooling rack.
Nutrition Facts
Monster Cookies
Amount Per Serving (1 cookie)
Calories 157 Calories from Fat 72
% Daily Value*
Fat 8g12%
Saturated Fat 4g25%
Cholesterol 17mg6%
Sodium 114mg5%
Potassium 48mg1%
Carbohydrates 20g7%
Fiber 1g4%
Sugar 14g16%
Protein 3g6%
Vitamin A 127IU3%
Vitamin C 1mg1%
Calcium 21mg2%
Iron 1mg6%
* Percent Daily Values are based on a 2000 calorie diet.

Nutrition Disclaimer: All information presented on this site is intended for informational purposes only. I am not a certified nutritionist and any nutritional information shared on should only be used as a general guideline.

This post was originally published in March 2015.  It was updated with new photos March 2020.

These monster cookie are our family's favorite recipe! They're easy to make and full of peanut butter, oats, and candy! You'll love this cookie recipe as much as we do!


These monster cookie are our family's favorite recipe! They're easy to make and full of peanut butter, oats, and candy! You'll love this cookie recipe as much as we do!