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Monster Cookies

Monster cookies are thick, chewy peanut butter cookies packed with M&Ms, chocolate chips, and oats in every bite. Baked to golden edges with soft, slightly underdone centers for that classic chunky texture.
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Prep Time 15 minutes
Cook Time 12 minutes
Total Time 27 minutes
Servings: 24 servings
Course: Dessert
Cuisine: American
Calories: 240
Ingredients Equipment Method Notes

Ingredients
  

peanut butter cookie dough
  • 1.5 cup creamy peanut butter
  • 1 cup brown sugar, packed
  • 0.5 cup granulated sugar
  • 3 large eggs
  • 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 preheat
  1. Preheat oven to 350°F and line two baking sheets with parchment paper. Arrange racks so the cookies bake evenly and don’t crowd the trays.
Make the dough
  1. Beat creamy peanut butter, brown sugar, packed, and granulated sugar together until combined. Mix until the mixture looks smooth and slightly glossy, with no dry sugar visible.
  2. Add large eggs, vanilla extract, and baking soda and mix until smooth. Scrape the bowl as needed so no streaks remain.
  3. Stir in quick-cooking oats until fully incorporated. The dough should look thick with oat pieces evenly distributed.
  4. Fold in M&Ms (red, white, and blue for patriotic version), chocolate chips, and mini chocolate chips. Distribute the mix-ins so color and chips show throughout the dough.
Shape and bake
  1. Scoop dough into 2-tablespoon balls and place 2 inches apart on prepared baking sheets. Flatten each slightly with your palm so the cookies bake into thick rounds.
  2. Bake for 10–12 minutes at 350°F until edges are set but centers still look slightly underdone. Look for golden edges with a soft center that doesn’t look fully dry.
Cool
  1. Let cookies cool on the baking sheet for 5 minutes before transferring to a wire rack. Cookies firm up as they cool, and the centers finish setting.

Notes

For thicker, chewier monster cookies, use fully packed brown sugar and avoid overbaking—pull them when edges look set but centers still look slightly underdone. Store in an airtight container at room temperature for up to 5 days or refrigerate up to 7 days; freeze baked cookies up to 2 months. To keep them gluten free, confirm your quick-cooking oats and M&Ms are certified gluten-free.