Monster Cookie Bars Recipe
Introduction
Monster Cookie Bars are a deliciously chewy and colorful treat packed with oats, chocolate chips, and M&M’s. These bars combine peanut butter and rich brown sugar for extra depth of flavor, making them perfect for satisfying your sweet tooth.

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
- 2 cups (304g) all-purpose flour
- 1 cup (100g) rolled oats
- 1 tsp baking soda
- 1/2 tsp baking powder
- 1/2 tsp salt
- 1 cup (200g) semi sweet chocolate chips
- 3/4 cup (150g) M&M’s
Instructions
- Step 1: Line a 9×9 inch pan with parchment paper and set aside.
- Step 2: Preheat the oven to 350°F (180°C).
- Step 3: Cream together the softened butter, peanut butter, brown sugar, and granulated sugar until smooth and creamy.
- Step 4: Add the eggs and vanilla extract, mixing until well combined.
- Step 5: Stir in the flour, rolled oats, baking soda, baking powder, and salt until a sticky dough forms.
- Step 6: Fold in the chocolate chips and M&M’s evenly through the dough.
- Step 7: Pour the mixture into the prepared pan and loosely press it down to pack the dough.
- Step 8: Bake for 25-30 minutes, or until the top is golden brown.
- Step 9: Allow the cookie bars to cool completely before removing them from the pan and cutting into squares.
- Step 10: Enjoy your delicious Monster Cookie Bars!
Tips & Variations
- Substitute M&M’s with chopped nuts or dried fruit for a different texture and flavor.
- For a softer texture, reduce baking time slightly and check bars at 20-25 minutes.
- Chill the dough for 30 minutes before baking for thicker bars.
Storage
Store the cookie bars in an airtight container at room temperature for 3-4 days. To keep them fresh longer, refrigerate for up to a week. Warm bars slightly in the microwave before serving for a gooey treat.
How to Serve

Serve this delicious recipe with your favorite sides.
FAQs
Can I use natural peanut butter instead of creamy?
Yes, natural peanut butter can be used, but it may alter the texture slightly due to its thinner consistency. Mixing it well before measuring helps ensure accurate quantity.
Can I freeze Monster Cookie Bars?
Absolutely. Wrap bars tightly in plastic wrap and place in a freezer-safe container. Freeze for up to 2 months. Thaw at room temperature before enjoying.
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Monster Cookie Bars Recipe
- Total Time: 40-45 minutes
- Yield: 16 bars 1x
Description
These Monster Cookie Bars combine the best of classic cookie flavors with a chewy, bar-shaped twist. Packed with peanut butter, oats, chocolate chips, and colorful M&M’s, these bars are perfect for satisfying your sweet tooth with a rich and delightful texture. Easy to prepare and baked until golden brown, they make an ideal treat for any occasion.
Ingredients
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 the pan: Line a 9×9 inch baking pan with parchment paper and set it aside to prevent sticking and ensure easy removal later.
- Preheat the oven: Set your oven to 350°F (180°C) to allow it to reach the perfect temperature for baking the cookie bars evenly.
- Cream butter and sugars: In a large bowl, cream together the softened salted butter, peanut butter, brown sugar, and granulated sugar until the mixture is smooth and creamy, ensuring even texture in your bars.
- Add eggs and vanilla: Incorporate the eggs and vanilla extract into the creamed mixture, beating until everything is well combined.
- Mix dry ingredients: Gradually add the all-purpose flour, rolled oats, baking soda, baking powder, and salt into the wet mixture, stirring until a sticky dough forms.
- Fold in chocolate and M&M’s: Gently mix in the semi-sweet chocolate chips and M&M’s to evenly distribute the colorful and chocolatey bits throughout the dough.
- Transfer dough to pan: Pour the cookie dough into the prepared baking pan, pressing and packing it down loosely to create an even layer.
- Bake the bars: Place the pan in the preheated oven and bake for 25-30 minutes, or until the tops turn golden brown and a toothpick inserted comes out with a few moist crumbs.
- Cool and cut: Allow the cookie bars to cool completely in the pan before lifting them out using the parchment paper, then cut into squares or bars as desired.
- Serve and store: Enjoy immediately or store the bars in an airtight container at room temperature for 3-4 days to keep them fresh.
Notes
- Ensure the butter is softened to room temperature for easier creaming with sugars.
- Do not overbake; the bars should be golden but still moist inside.
- You can substitute M&M’s with other colorful candies or nuts for variation.
- For easier removal, let the bars cool completely before slicing.
- Store the bars in an airtight container to maintain freshness and chewiness.
- 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 bars, oatmeal cookie bars, easy cookie bars, M&M cookie bars

