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Monster Cookies

Monster cookies are thick, chewy peanut butter cookies loaded with M&Ms, chocolate chips, and oats for visible texture in every bite. They bake up with golden edges and soft centers using a quick mix-and-scoop method.
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Prep Time 15 minutes
Cook Time 12 minutes
Total Time 27 minutes
Servings: 24 servings
Course: Dessert
Cuisine: American
Calories: 330
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 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
 

Preheat and prep
  1. Preheat the oven to 350°F and line two baking sheets with parchment paper, using a wire-rack-friendly setup for easy transferring later.
Mix the cookie dough
  1. Beat the creamy peanut butter, brown sugar, and granulated sugar together in a large bowl until combined and glossy.
Add wet ingredients
  1. Add the large eggs, vanilla extract, and baking soda, then mix until smooth with no streaks.
Add oats and mix-ins
  1. Stir in the quick-cooking oats until fully incorporated, then fold in the M&Ms, chocolate chips, and mini chocolate chips so they’re evenly distributed.
Scoop and shape
  1. Scoop dough into 2-tablespoon balls and place them 2 inches apart on the prepared baking sheets, flattening each slightly with your palm for even baking.
Bake
  1. Bake at 350°F for 10–12 minutes until the edges are set but the centers still look slightly underdone, looking thicker and puffed with golden rims.
Cool and set
  1. Let the cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack where they firm up as they cool.

Notes

For thick, chewy cookies, keep the dough portions consistent and don’t overbake—pull them when centers still look a bit soft. Store airtight at room temperature for up to 4 days or refrigerate for up to 7 days; freeze baked cookies for up to 2 months. Dietary swap: for gluten-free, use certified gluten-free oats while keeping all other ingredients the same.