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Monster Cookies

Monster cookies are thick, chewy peanut butter cookies with oats visible in every bite and colorful M&Ms baked into a soft center. This easy no-flour-style dough (no wheat flour added) turns out golden-edged cookies that cool into a firm, chewy 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: 270
Ingredients Equipment Method Notes

Ingredients
  

Peanut butter cookie base
  • 1.5 cup creamy peanut butter Use creamy peanut butter for a smooth, thick dough.
  • 1 cup brown sugar, packed Pack firmly for chewy sweetness.
  • 0.5 cup granulated sugar Helps balance the cookie chew.
  • 3 large eggs Room temperature eggs mix more evenly.
  • 2 tsp vanilla extract
  • 1 tsp baking soda
  • 3 cup quick-cooking oats Visible oats are part of the monster-cookie texture.
  • 1 cup M&Ms (red, white, and blue for patriotic version) Adds color in every bite.
  • 0.5 cup chocolate chips
  • 0.5 cup mini chocolate chips Extra pockets of chocolate help keep the cookies interesting.

Equipment

  • 1 sheet pan

Method
 

Prep the oven and dough
  1. Preheat the oven to 350°F and line two baking sheets with parchment paper.
  2. Beat peanut butter, brown sugar, and granulated sugar together in a large bowl until combined.
  3. Add eggs, vanilla, and baking soda, then mix until smooth.
  4. Stir in oats until fully incorporated.
  5. Fold in M&Ms and 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.
  2. Flatten each dough ball slightly with your palm.
  3. Bake for 10–12 minutes at 350°F until edges are set but centers still look slightly underdone, with golden edges and a soft center.
  4. Let the cookies cool on the baking sheet for 5 minutes.
  5. Transfer to a wire rack so they firm up as they cool.

Notes

For the thick, chewy texture, don’t overbake—pull cookies when edges are set and centers still look a touch underdone. Store airtight at room temperature for up to 5 days; refrigerate up to 7 days. Freeze baked cookies for up to 2 months (thaw at room temperature). For a dietary swap, use certified gluten-free oats to keep the recipe gluten-free.