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Monster Cookies

Monster cookies are thick, chewy peanut butter cookies with oats and chocolate chips, loaded with M&Ms so color shows in every bite. Baked at 350°F until the edges set and the centers stay soft, then cooled briefly to finish the 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: 260
Ingredients Equipment Method Notes

Ingredients
  

Peanut butter cookie base
  • 1.5 cup creamy peanut butter Use creamy peanut butter for a smooth, chewy dough.
  • 1 cup brown sugar Packed brown sugar helps create chew and deep caramel flavor.
  • 0.5 cup granulated sugar Adds sweetness and helps spread for thick, tender cookies.
  • 3 eggs Large eggs for structure and moisture.
  • 2 tsp vanilla extract For warm flavor in every bite.
  • 1 tsp baking soda Helps the cookies stay soft and tender.
  • 3 cup quick-cooking oats Oats create the chewy, visible oat texture.
  • 1 cup M&Ms Use red, white, and blue for a patriotic version.
  • 0.5 cup chocolate chips Adds melty pockets throughout.
  • 0.5 cup mini chocolate chips Helps distribute chocolate flavor in every cookie bite.

Equipment

  • 1 sheet pan

Method
 

Prepare the oven
  1. Preheat the oven to 350°F and line two baking sheets with parchment paper.
  2. Set the baking sheets aside so they’re ready for scooping after the dough is mixed.
Mix the dough
  1. Beat peanut butter, brown sugar, and granulated sugar together in a large bowl until combined.
  2. Add eggs, vanilla, and baking soda, then mix until smooth.
  3. Stir in quick-cooking oats until fully incorporated.
  4. Fold in M&Ms, chocolate chips, and mini chocolate chips until evenly distributed.
Shape and bake
  1. Scoop dough into 2-tablespoon balls and place 2 inches apart on the prepared baking sheets, flattening slightly with your palm.
  2. Bake for 10–12 minutes at 350°F until the edges are set but the centers still look slightly underdone.
  3. Let cool on the baking sheet for 5 minutes before transferring to a wire rack so cookies firm up as they cool.

Notes

Pro tip: For the thick, chewy texture, don’t overbake—pull the cookies when centers still look a little underdone. Store in an airtight container at room temperature for up to 5 days. Freeze baked cookies for up to 2 months; thaw at room temperature. If you need gluten-free, use certified gluten-free oats (and check M&Ms label) to keep the cookie texture similar.