Monster Cookie Bars
Monster cookie bars- soft and chewy peanut butter oatmeal cookie bars loaded with colorful M&Ms and chocolate chips! Inspired by monster cookies, these quick and easy bakery-style dessert bars are made in one bowl in less than 1 hour.
Equipment
Ingredients
- 14 tablespoon unsalted butter room temperature
- ½ cup creamy peanut butter
- ½ cup light brown sugar packed
- ½ cup dark brown sugar packed
- ½ cup granulated sugar
- 2 large eggs room temperature
- 2 large egg yolks room temperature
- 1 tablespoon vanilla extract
- 2 cups all-purpose flour *See notes below for measuring*
- 1 ¾ cup rolled oats (old-fashioned oats)
- ½ cup semi-sweet chocolate chips
- ½ cup chopped chocolate bar
- ⅓ cup mini M&Ms
- ⅓ cup regular M&Ms
- 1 teaspoon baking soda
- 1 teaspoon fine sea salt
Instructions
- Line a 9x13 baking pan with parchment paper or grease the sides and bottom with nonstick spray or butter. Then preheat the oven to 350 F/180 C.
- In a mixing bowl, cream the butter, peanut butter, brown sugar, and granulated sugar until light and fluffy.
- Mix in the eggs, egg yolks, and vanilla.
- Fold in the flour, oats, baking soda, salt, chocolate chips, chopped chocolate, and M&Ms until just combined. Do not overmix! Evenly spread the cookie dough into the prepared baking pan. Sprinkle the top with extra chocolate chips, chopped chocolate, and M&Ms if desired.
- Bake in the preheated oven for 25-35 minutes or until the top is golden brown and a toothpick inserted into the center comes out just barely moist. Let them cool completely on a wire rack before cutting then enjoy!
Video
Notes
*Measure your flour properly. This is my #1 baking tip! Do not ever scoop a measuring cup into your flour as this always leads to using too much flour. Instead, use the spoon-level method. This means fluffing the flour first, then spooning it into your measuring cup/spoon. For the BEST results, use a kitchen scale!*