Description

Delightfully chewy and packed with chocolate chips, M&M’s, and oats, these Monster Cookie Bars bring together the perfect combination of peanut butter richness and classic cookie flavors. Baked in a 9×9 pan for easy slicing, they make a great treat for sharing or an indulgent snack.

Ingredients

Scale

Wet Ingredients

1/2 cup (111g) salted butter, softened
1/4 cup (62g) peanut butter
1 cup (246g) brown sugar
1/4 cup (58g) granulated sugar
2 eggs
2 tsp vanilla extract

Dry Ingredients

2 cups (304g) all-purpose flour
1 cup (100g) rolled oats
1 tsp baking soda
1/2 tsp baking powder
1/2 tsp salt

Add-ins

1 cup (200g) semi sweet chocolate chips
3/4 cup (150g) M&M’s

Instructions

Prepare Pan: Line a 9×9 inch baking pan with parchment paper to prevent sticking and set aside.
Preheat Oven: Preheat your oven to 350°F (180°C), ensuring it’s fully heated before baking.
Cream Butter and Sugars: In a large mixing bowl, beat together the softened butter, peanut butter, brown sugar, and granulated sugar until the mixture is smooth and creamy.
Add Eggs and Vanilla: Incorporate the eggs and vanilla extract into the creamed butter mixture and mix thoroughly until combined.
Add Dry Ingredients: Add the all-purpose flour, rolled oats, baking soda, baking powder, and salt. Mix until a sticky dough forms and all ingredients are well incorporated.
Fold in Chocolate and M&M’s: Gently mix in the semi-sweet chocolate chips and M&M’s to distribute evenly throughout the dough.
Transfer to Pan: Pour the cookie dough into the prepared pan. Loosely press and pack the dough evenly to fill the pan.
Bake: Bake in the preheated oven for 25-30 minutes, or until the tops are golden brown and a toothpick inserted near the center comes out mostly clean with a few moist crumbs.
Cool: Remove the pan from the oven and allow the bars to cool completely in the pan on a wire rack before lifting out and cutting into bars.
Serve and Store: Enjoy your Monster Cookie Bars fresh. Store any leftovers in an airtight container at room temperature for 3-4 days to maintain freshness.

Notes

Ensure butter is softened but not melted for best creaming results.
You can substitute M&M’s with your favorite candy pieces or nuts if desired.
For chewier bars, slightly underbake and let them cool fully to set.
These bars can also be wrapped and frozen for up to 2 months; thaw before serving.
Use parchment paper hanging over the sides of the pan for easy removal of bars.

Prep Time: 15 minutes
Cook Time: 25-30 minutes
Category: Dessert
Method: Baking
Cuisine: American

Keywords: Monster Cookie Bars, peanut butter cookie bars, chocolate chip cookie bars, M&M cookie bars, easy dessert bars, baking treats