Description
These Monster Cookie Bars are thick, chewy, and loaded with peanut butter, oats, chocolate chips, and M&M's—everything you love in one colorful, gluten-free dessert. Perfect for parties, meal prep, or a sweet snack, these easy one-bowl bars are freezer-friendly and totally customizable.
Ingredients
- ½ cup unsalted butter, room temperature
- 1 cup creamy peanut butter
- 1 cup packed light brown sugar
- ½ cup granulated sugar
- 2 large eggs
- 1 tsp vanilla extract
- 3 cups old-fashioned oats
- 1 tsp baking soda
- ½ tsp salt
- 1 cup semi-sweet chocolate chips
- 1 cup M&M's (plus extra for topping)
Instructions
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Preheat oven to 350°F (175°C). Line a 9x13-inch baking pan with parchment paper or lightly grease.
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In a large bowl, cream together butter, peanut butter, brown sugar, and granulated sugar until smooth and fluffy.
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Beat in the eggs one at a time. Add vanilla and mix well.
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Stir in oats, baking soda, and salt until combined.
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Fold in chocolate chips and most of the M&M’s, reserving some for topping.
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Spread the dough evenly into the prepared pan. Press remaining M&M’s on top.
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Bake for 25–30 minutes, until edges are golden and center is set.
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Let cool completely before slicing into bars.
Notes
- Use old-fashioned oats for the best chewy texture.
- Don’t overbake—pull them when the center still looks slightly soft.
- Swap peanut butter with almond or sunflower seed butter for dietary needs.
- Add-ins like nuts, coconut flakes, or white chocolate chips add a fun twist.
- Store airtight at room temp, in the fridge, or freeze individually for later.
