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Stack of delicious Big Giant Monster Cookies, oatmeal chocolate chip with vibrant M&Ms, on a marble surface.

Big Giant Monster Cookies

These ultimate chewy, loaded, and flourless monster cookies are packed with peanut butter, oats, chocolate chips, and M&M's, offering a delightful treat for any occasion.
Prep Time 20 minutes
Cook Time 15 minutes
Total Time 35 minutes
Servings 24 cookies
Calories 320 kcal

Equipment

  • Hand mixer
  • Stand mixer
  • Large bowl
  • Parchment paper
  • Baking sheets
  • wire racks
  • airtight container

Ingredients
  

Main Ingredients

  • 2 cups creamy peanut butter
  • 2/3 cup butter, softened
  • 1-1/3 cups sugar
  • 1-1/3 cups packed brown sugar
  • 4 large eggs room temperature
  • 2-1/2 teaspoons baking soda
  • 1 teaspoon vanilla extract
  • 1 teaspoon light corn syrup
  • 6 cups old-fashioned oats
  • 1 cup semisweet chocolate chips
  • 1 cup milk chocolate M&M's

Instructions
 

Preparation

  • Preheat the oven to 350°F. In a large bowl, cream together the peanut butter, softened butter, sugar, and brown sugar using a mixer for five to seven minutes until light and fluffy. Then, beat in the eggs, baking soda, vanilla extract, and corn syrup until the mixture is homogenous.
  • Add the old-fashioned oats and beat well. Gently fold in the semisweet chocolate chips and milk chocolate M&M's, then cover the dough and refrigerate for one hour.
  • Drop the chilled dough by 1/4 cupfuls onto parchment-lined baking sheets, ensuring each cookie is spaced about 3 inches apart.
  • Bake the cookies for 14 to 18 minutes, or until the edges are lightly browned. Allow the cookies to cool on the baking sheets at room temperature for five minutes before transferring them to wire racks to cool completely. Store the cooled cookies in an airtight container.

Notes

Ensure butter and eggs are at room temperature for best creaming results. Do not overbake the cookies; they will set more as they cool. Chilling the dough is crucial for proper texture and to prevent spreading.