Go Back
+ servings
Closeup of monster cookie bars laid out on a tray.
Print Recipe
5 from 2 votes

Monster Cookie Bars

Monster Cookie Bars are the ultimate cookie mashup because they are chock full of oatmeal, peanut butter, M&Ms, and chocolate chips! Soft and chewy cookies in a one-bowl recipe.
Prep Time15 minutes
Cook Time20 minutes
Total Time35 minutes
Course: Dessert
Cuisine: American
Servings: 16 2x2 squares
Calories: 333kcal
Author: Rachel

Ingredients

Oatmeal Cookie Bars

  • ½ cup Unsalted Butter softened
  • 1 cup Light Brown Sugar
  • 1 teaspoon Vanilla Extract
  • 2 Eggs
  • 2 cup All-Purpose Flour
  • 2 cup Old-fashioned Oats
  • ½ cup Peanut Butter Creamy or Crunchy
  • 1 teaspoon Baking Soda
  • ½ teaspoon Salt
  • 1 cup Chocolate Chips about 6 ounces
  • 1 cup M&Ms

Instructions

  • Preheat oven to 350 degrees F. Grease a 9x13 deep pan and set aside.
  • In a large mixing bowl, combine butter, brown sugar, and vanilla until smooth. Break eggs and beat until smooth. Add in flour, oats, peanut butter, baking soda, and salt. You can use a stand mixer or electric mixer or hand mix.
  • Using a large spoon, stir in the chocolate chips and half the M&Ms to the batter.
  • Press batter into greased baking dish. Sprinkle remaining M&Ms on the top, pressing them into the dough slightly.
  • Bake for 15-18 minutes or until the edges crisp and slightly brown or a toothpick comes out clean. Let cool a bit before slicing. Letting them cool completely is best, but who could wait that long!

Notes

Store: These can be stored in an air-tight container at room temperate for 3-4 days.
Freeze: You may freeze these bars to enjoy for later and they should last about 2 months. I recommend cutting and wrapping the bars individually to prevent sticking.
Make ahead dough: The dough can be prepared and stored in the refrigerator up to 48 hours ahead of time. It also freezes well. Make sure it is in an air-tight container and brought to room temperature on the counter before baking.

Nutrition

Serving: 50g | Calories: 333kcal | Carbohydrates: 54g | Fat: 12.8g | Saturated Fat: 8g | Cholesterol: 29mg | Sodium: 320mg | Potassium: 114mg | Sugar: 12g | Calcium: 600mg | Iron: 0.2mg