Thick and Chewy Monster Cookies

  • Author: Melissa
  • Prep Time: 10 minutes
  • Cook Time: 11 minutes
  • Total Time: 21 minutes
  • Yield: 2 dozen 1x


These Thick and Chewy Monster cookies are loaded with peanut butter, chocolate chips, and M&Ms. I love that these cookies are made with old fashioned oats to add texture in every bite!



  • 1/2 cup (115 grams)unsalted butter, softened to room temperature
  • 1/2 cup (108 grams) packed light brown sugar
  • 1/4 cup (50 grams) granulated sugar
  • 3/4 cup (185 grams) creamy peanut butter
  • 1 large egg
  • 1 teaspoon vanilla extract
  • 1/2 teaspoon baking soda
  • 1/4 teaspoon salt
  • 11/4 cup all-purpose flour, spooned and leveled
  • 3/4 cups (75 grams) old fashioned, whole oats or rolled oats
  • 3/4 cup  (150 grams) M&Ms
  • 1/2 cup (90 grams) semi-sweet chocolate chips


  1. Preheat the oven to 350 degrees Fahrenheit.
  2. First, cream together the butter, brown sugar and granulated sugar until light and fluffy. Then, combine in the creamy peanut butter. Then, stir in the egg and vanilla.
  3. Measure out the baking soda, salt, all-purpose flour, and old fashioned oats. Slowly add into the wet mixture, until combined. Be sure not to overmix.
  4. Use a spatula, and add in M&Ms and chocolate chips. Feel free to reserve some M&Ms for later to press into the tops of the cookie dough balls before baking. Combine well to make sure the M&Ms and chocolate chips are well dispersed throughout the batter.
  5. Measure out about 2 tablespoons of dough and roll into a ball, and place onto the prepared cookie sheet about 2 inches apart. Place the most colorful side (from the M&Ms and chocolate chips) of the cookie ball facing up.
  6. These cookies do not spread much, so you will want to lightly press down on the cookie. They were about 1 inch thick when I pressed mine. Add any reserved M&Ms to the tops of the cookies to add more color if needed.
  7. Bake for 11-13 minutes. Cookies will still look soft. Do not wait for the browning of the cookie base as this will overbake these cookies, and cause them to be crispy.
  8. Allow cookies to cool on the cookie pan for about 10 minutes before transferring to a cooling rack. This will allow the cookies to firm up as they are really soft just out of the oven.


These cookies will store for up to a week covered at room temperature, or up to three months frozen.

  • Category: Cookies
  • Method: Bake
  • Cuisine: American

Keywords: Thick and chewy monster cookies