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+ servings
the BEST Monster Cookies Recipe

Monster Cookies

Thick and chewy Monster Cookies made with oats, peanut butter, M&M candies, and chocolate chips. These are always a huge hit with family and friends.
Course Dessert
Cuisine American
Keyword chocolate chip, cookie, halloween, M&M's, monster
Prep Time 10 minutes
Cook Time 13 minutes
Servings 24 cookies


  • ½ cup butter - softened (1 stick)
  • ½ cup creamy peanut butter
  • ½ cup granulated sugar
  • ½ cup brown sugar - firmly packed
  • 1 large egg
  • 1 tsp vanilla extract
  • cup quick cook oats
  • 1 cup all-purpose flour
  • ½ tsp baking powder
  • ½ tsp baking soda
  • tsp table salt
  • ½ cup standard M&M's + more for the tops
  • ¼ cup mini M&M's + more for the tops
  • ¼ cup mini chocolate chips + more for the tops

Halloween Monster Cookie Add-Ins

  • ½ cup Halloween M&M's
  • ¼ cup candy corn
  • candy eyes


  • Preheat the oven to 350 degrees.
  • Line 2-3 baking sheets with parchment and then set aside.
  • In a large mixing bowl, combine the butter, and peanut butter - beat until smooth.
  • Add the granulated sugar, brown sugar, eggs and vanilla - beat until blended.
  • Next add the oats, flour, baking powder, baking soda and salt. Stir until just blended.
  • Fold in both types of M&M's and the chocolate chips.
  • Scoop out the dough and roll between your hands to form into balls - about the size of a golf ball.
  • Place on the prepared baking sheets about 2" apart.
  • Bake for 12-13 minutes or until golden brown.
  • Remove from the oven and immediately add additional M&M"s and chocolate chips as desired.
  • Transfer to a wire rack to cool completely before storing in an airtight container.

Halloween Monster Cookie

  • When making the Halloween version - swap out the M&M's and replace the chocolate chips with the candy corn.
  • Add the eyes and additional candy corn after baking.


  • I’m using Halloween-colored M&Ms, but feel free to use any add-ins you like.
  • If you add candy corn to the cookie dough, make sure they are fully encased in the
    dough when you bake them or they’ll melt in the oven. I recommend adding them on top of the cookies if you want to keep the shape.
  • Candy eyes add a fun Halloween twist as well, but they are completely optional! Just make sure to press them into the cookies while they’re still warm so they stick