Go Back
Broken monster cookie showing a soft chewy oatmeal peanut butter center

Monster Cookies

Soft and chewy monster cookies loaded with peanut butter, oats, M&M’s, and chocolate chips. This easy flourless monster cookie recipe is freezer-friendly and perfect for big batches.
Print Recipe Pin Recipe
Prep Time 15 minutes
Cook Time 12 minutes
20 minutes
Total Time 47 minutes
Servings: 24 cookies
Course: Cookies, Dessert
Cuisine: American
Calories: 210
Ingredients Equipment Method Notes

Ingredients
  

  • 1/2 cup unsalted butter softened
  • 1 cup creamy peanut butter
  • 1 cup packed light brown sugar
  • 1/2 cup granulated sugar
  • 2 large eggs room temperature
  • 2 teaspoons vanilla extract
  • 2 cups old-fashioned rolled oats
  • 1 cup quick oats
  • 1 teaspoon baking soda
  • 1/2 teaspoon fine salt
  • 1 1/2 cups M&M’s plus extra for topping
  • 1 cup semi-sweet chocolate chips
  • 1/2 cup chopped pretzels or nuts optional

Equipment

  • 2 Baking sheets lined with parchment paper
  • 1 Large mixing bowl for cookie dough
  • 1 Medium mixing bowl, optional for oats and dry ingredients
  • 1 Electric mixer hand mixer or stand mixer
  • 1 Rubber spatula for folding in mix-ins
  • 1 Cookie scoop 2 to 3 tablespoon size
  • 1 Wire rack for cooling cookies
  • 1 Measuring cups and spoons for accurate measuring

Method
 

  1. Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper.
  2. In a large bowl, beat the softened butter, peanut butter, brown sugar, and granulated sugar for about 2 minutes until smooth and slightly fluffy.
  3. Add the eggs one at a time, then mix in the vanilla extract until fully combined.
  4. Add the old-fashioned oats, quick oats, baking soda, and salt. Mix on low speed or stir until evenly combined.
  5. Fold in the M&M’s, chocolate chips, and optional pretzels or nuts.
  6. Chill the dough for 20 to 30 minutes if it feels soft or sticky.
  7. Scoop 2 to 3 tablespoon portions of dough onto the prepared baking sheets, spacing them about 2 inches apart.
  8. Press a few extra M&M’s or chocolate chips on top of each dough ball.
  9. Bake for 10 to 12 minutes, until the edges are set and the centers still look soft.
  10. Cool the cookies on the baking sheet for 10 minutes, then transfer to a wire rack to cool completely.

Notes

Use regular creamy no-stir peanut butter for the most reliable texture. Natural peanut butter can make the dough greasy if it is not stirred very well.
For gluten-free monster cookies, use certified gluten-free oats and check that your candy and chocolate chips are gluten-free.
Do not overbake. The centers should still look soft when the cookies come out of the oven.
For thicker cookies, chill the dough for 30 minutes before baking.
Store baked cookies in an airtight container at room temperature for up to 5 days.
Freeze baked cookies or unbaked dough balls for up to 2 months.