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Monster Cookies

Monster cookies are thick, chewy peanut-butter cookies studded with M&Ms, chocolate chips, and visible oats in every bite. Baked at 350°F until the edges set but the centers stay soft, then cooled to firm up for a chewy finish.
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Prep Time 15 minutes
Cook Time 12 minutes
Total Time 27 minutes
Servings: 24 servings
Course: Dessert
Cuisine: American
Calories: 310
Ingredients Equipment Method Notes

Ingredients
  

Peanut butter cookie base
  • 1.5 cup creamy peanut butter
  • 1 cup brown sugar, packed
  • 0.5 cup granulated sugar
  • 3 eggs large
  • 2 tsp vanilla extract
  • 1 tsp baking soda
  • 3 cup quick-cooking oats
  • 1 cup M&Ms (red, white, and blue for patriotic version)
  • 0.5 cup chocolate chips
  • 0.5 cup mini chocolate chips

Equipment

  • 1 sheet pan

Method
 

Prep and heat
  1. Preheat the oven to 350°F and line two baking sheets with parchment paper.
Mix the cookie dough
  1. Beat the creamy peanut butter, brown sugar, and granulated sugar together until combined.
  2. Add the eggs, vanilla extract, and baking soda, then mix until smooth.
  3. Stir in the quick-cooking oats until fully incorporated.
  4. Fold in the M&Ms and both chocolate chip types so the mix looks evenly speckled.
Shape and bake
  1. Scoop the dough into 2-tablespoon balls and place them 2 inches apart on the prepared baking sheets.
  2. Flatten each ball slightly with your palm so the cookies bake into thick, even rounds.
  3. Bake for 10–12 minutes at 350°F until the edges look set but the centers still look slightly underdone.
Cool and set
  1. Let the cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack so they firm up as they cool.

Notes

For the thick, chewy texture, don’t overbake—pull the cookies when the centers still look a touch soft. Store airtight at room temperature for up to 4 days or refrigerate up to 1 week; freeze baked cookies up to 2 months. For a gluten-free version, confirm your quick-cooking oats are certified gluten-free (the recipe itself is no-flour).