Monster Cookie Bars
These Monster Cookie Bars are chewy, colorful, and packed with oats, peanut butter, chocolate chips, and M&M’s. Baked in one pan, they’re an easy and fun dessert perfect for parties, potlucks, or anytime you need a sweet crowd-pleaser.
Ingredients
- 1/2 cup unsalted butter softened
- 1 cup brown sugar packed
- 1/2 cup granulated sugar
- 1 cup creamy peanut butter
- 2 large eggs
- 1 teaspoon vanilla extract
- 1 teaspoon baking soda
- 1/2 teaspoon salt
- 2 cups old-fashioned oats
- 1 1/2 cups all-purpose flour
- 1 cup semi-sweet chocolate chips
- 1 cup candy-coated chocolates like M&M’s, plus extra for topping
Instructions
- Preheat oven to 350°F (175°C). Grease or line a 9x13-inch baking pan with parchment paper.
- In a large bowl, cream together butter, brown sugar, and granulated sugar until fluffy.
- Mix in peanut butter, eggs, and vanilla until smooth.
- Stir in baking soda, salt, oats, and flour until combined.
- Fold in chocolate chips and 3/4 cup of the M&M’s.
- Spread dough evenly in the pan and sprinkle extra M&M’s on top.
- Bake 25–30 minutes, until edges are golden and center is set.
- Cool completely before cutting into bars.
Notes
- For a bakery-style look, press extra M&M’s on top after baking while still warm.
- Slightly underbake for chewier bars; they’ll firm up as they cool.
- Swap in holiday-colored M&M’s for seasonal treats.
- Store at room temperature in an airtight container for up to 5 days or freeze up to 2 months.