Monster Cookie Bars Recipe
Introduction
Monster Cookie Bars are a delightful treat full of rich peanut butter, oats, and colorful candy. These bars combine chewy textures and sweet flavors that are perfect for any snack or dessert craving.

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 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 semi sweet chocolate chips and M&M’s evenly through the dough.
- Step 7: Pour the mixture into the prepared pan and loosely press and pack the dough into the pan.
- Step 8: Bake for 25-30 minutes, or until the tops are golden brown and a toothpick comes out clean.
- 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
- For extra chewiness, substitute half the all-purpose flour with whole wheat flour or oat flour.
- Add chopped nuts like walnuts or pecans for added crunch and flavor.
- Use peanut butter chips or white chocolate chips instead of semi sweet chocolate for a different twist.
- Press a few extra M&M’s or chocolate chips on top before baking for a colorful presentation.
Storage
Store the Monster Cookie Bars in an airtight container at room temperature for 3-4 days. To keep them fresh longer, you can refrigerate them for up to a week. Reheat individual bars in the microwave for 10-15 seconds for a soft, warm treat.
How to Serve

Serve this delicious recipe with your favorite sides.
FAQs
Can I use creamy peanut butter instead of chunky?
Yes, creamy peanut butter works perfectly in this recipe and will blend smoothly into the dough.
Can I freeze Monster Cookie Bars?
Absolutely! Wrap the cooled bars tightly in plastic wrap and place them in a freezer-safe container. They can be frozen 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 are a deliciously chewy and colorful treat combining classic cookie ingredients with fun additions like peanut butter, rolled oats, chocolate chips, and M&M’s. Perfect for satisfying sweet cravings with a rich, nutty flavor and satisfying texture.
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
Mix-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 and set aside to prevent sticking and ease removal of the bars.
- Preheat Oven: Heat your oven to 350°F (180°C) to reach the correct baking temperature.
- Cream Butters and Sugars: In a mixing bowl, cream together the softened butter, peanut butter, brown sugar, and granulated sugar until the mixture is smooth and creamy, ensuring proper incorporation for a tender texture.
- Add Eggs and Vanilla: Beat in the eggs and vanilla extract until the mixture is well combined and smooth.
- Mix Dry Ingredients: In a separate bowl, whisk together the all-purpose flour, rolled oats, baking soda, baking powder, and salt to evenly distribute the leavening agents and salt.
- Combine Wet and Dry: Gradually add the dry ingredients to the wet ingredients, mixing until a sticky dough forms, ensuring the components are fully incorporated without overmixing.
- Add Chocolate Chips and M&M’s: Fold in the semi-sweet chocolate chips and M&M’s, distributing them evenly throughout the dough for bursts of chocolate and color.
- Transfer and Pack Dough: Pour the dough into the prepared pan and loosely press and pack it evenly to ensure uniform baking and thickness.
- Bake: Place the pan in the preheated oven and bake 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: Allow the cookie bars to cool completely in the pan to set and firm up before removing.
- Cut and Serve: Once cooled, lift the bars out of the pan using the parchment paper and cut into squares. Enjoy your Monster Cookie Bars!
- Storage: Store any leftovers in an airtight container at room temperature for 3-4 days to maintain freshness.
Notes
- Use parchment paper to ensure easy removal of the bars without sticking.
- Do not overbake; the bars should be golden but still moist inside.
- You can substitute crunchy peanut butter for smooth if desired for extra texture.
- For a nut-free version, omit the peanut butter and replace with additional butter or a seed butter.
- Allow bars to cool completely before cutting to prevent crumbling.
- Prep Time: 15 minutes
- Cook Time: 25-30 minutes
- Category: Dessert
- Method: Baking
- Cuisine: American
Keywords: Monster Cookie Bars, Peanut Butter Cookies, Chocolate Chip Bars, Oatmeal Cookies, M&M Cookies, Easy Cookie Bars, Chewy Cookie Bars

