Are you ready to treat yourself to a delightful dessert? My Chewy Monster Cookie Bars are a fun twist on classic cookie flavor. With creamy peanut butter chips, colorful M&M's, and a chewy texture, these bars will become your new favorite. In this easy recipe, I’ll guide you step-by-step to create these delicious treats that are perfect for parties, snacks, or just a sweet craving. Let’s get started!
Why I Love This Recipe
- Irresistible Flavor: These cookie bars combine the rich taste of chocolate, peanut butter, and oats, creating a delightful treat that satisfies every sweet tooth.
- Easy to Make: With simple ingredients and straightforward steps, these bars come together quickly, making them perfect for a last-minute dessert.
- Perfect for Sharing: Cut them into squares and share with friends or family; they are always a hit at gatherings, parties, or bake sales.
- Customizable: You can easily swap in your favorite mix-ins or adjust the types of chips used, making these bars adaptable to your taste preferences.
Ingredients
List of Ingredients
- 1 cup unsalted butter, softened
- 1 cup brown sugar, packed
- ½ cup granulated sugar
- 2 large eggs
- 1 teaspoon vanilla extract
- 2 cups all-purpose flour
- 1 teaspoon baking soda
- ½ teaspoon salt
- 1 cup rolled oats
- ½ cup semi-sweet chocolate chips
- ½ cup milk chocolate chips
- ½ cup peanut butter chips
- ½ cup M&M's candies
To make Chewy Monster Cookie Bars, gather all these tasty ingredients. Each one plays a key role in the final flavor and texture. Start with unsalted butter; it helps control the saltiness. Brown sugar gives a rich taste, while granulated sugar adds sweetness. The eggs bind everything together and add moisture.
Vanilla extract brings warmth to the bars. All-purpose flour is the base, while baking soda helps them rise. A pinch of salt balances the sweetness. Rolled oats add chewiness and fiber. The chocolate and peanut butter chips offer bursts of flavor. Lastly, M&M's add color and crunch.
These ingredients ensure your cookie bars are not just good but truly irresistible. Each bite will be a mix of soft, chewy, and crunchy. Get ready to enjoy a treat that is fun to make and even more fun to eat!

Step-by-Step Instructions
Prepping the Oven and Dish
- Preheat your oven to 350°F (175°C).
- Prepare a 9x13-inch baking pan by greasing it or lining it with parchment paper.
Mixing Wet Ingredients
- In a large bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy. This takes about 2-3 minutes.
- Add the eggs one at a time. Then mix in the vanilla extract until everything is well combined.
Combining Dry Ingredients
- In a separate bowl, whisk together the all-purpose flour, baking soda, and salt.
- Gradually add this dry mixture to the wet mixture. Stir until just blended; don’t overmix.
Adding Mix-ins
- Now fold in the rolled oats, semi-sweet chocolate chips, milk chocolate chips, peanut butter chips, and M&M's. Make sure they are evenly mixed into the dough.
Baking the Cookie Bars
- Pour the cookie dough into your prepared baking pan. Spread it evenly.
- Bake in the preheated oven for 20-25 minutes. Check for doneness when the edges are golden and the center is set but still chewy.
Cooling and Serving
- Let the cookie bars cool in the pan for about 10 minutes.
- After that, transfer them to a wire rack to cool completely.
- For a fun presentation, serve on a colorful platter. You can add a few more M&M's on top and drizzle with melted chocolate for extra flair!
Tips & Tricks
Achieving the Perfect Chewy Texture
To get that chewy texture, start with the butter. Make sure it's softened, not melted. Softened butter helps create the right blend in your dough.
Next, let's talk about mixing. Cream the butter and sugars well. This step adds air, which helps the bars rise. Mix just until combined after adding the dry ingredients to keep them soft.
Common Mistakes to Avoid
One big mistake is overmixing the dough. When you mix too much, your cookie bars can become tough. Mix gently and stop when you see no dry flour.
Another mistake is not checking your oven temperature. Use an oven thermometer to ensure it’s accurate. An oven too hot can burn the edges before the center cooks.
Enhancing Flavor & Texture
Want to boost flavor? Add nuts or dried fruits to your mix. Chopped walnuts or cranberries work great.
You can also add spices. A pinch of cinnamon adds warmth and depth. Just a half teaspoon will do. It will elevate your bars to a new level of yum!
Pro Tips
- Use Room Temperature Ingredients: Ensure your butter and eggs are at room temperature for a smoother batter and better incorporation of ingredients.
- Don’t Overmix the Dough: Mix the dry ingredients just until combined to avoid tough cookie bars. A few lumps are perfectly fine.
- Experiment with Mix-Ins: Feel free to swap out the chocolate and peanut butter chips for your favorite candies or nuts to create your own version!
- Check for Doneness: Bake until the edges are golden and the center is set but still slightly soft. They will continue to firm up as they cool.
Variations
Healthier Options
You can make Chewy Monster Cookie Bars healthier with simple swaps. First, try using whole wheat flour instead of all-purpose flour. Whole wheat flour adds fiber and nutrients. It also gives a nutty flavor.
Next, consider using sugar alternatives. You can use coconut sugar or stevia. These options lower the glycemic index. This means they can be better for your blood sugar levels. Always check the conversion ratios for these alternatives.
Flavor Variations
Want to change up the flavor? Use different types of chocolate chips. Try dark chocolate or white chocolate chips. Each type will change the taste and sweetness.
You can also add nuts or dried fruits. Chopped walnuts or almonds add crunch. Dried cranberries or cherries can give a sweet-tart flavor. Mix and match to find your favorite combo!
Customize for Seasons
Make your cookie bars fit the season! For holidays, use color candies like red and green M&M's for Christmas. In fall, try adding pumpkin spice for a warm flavor.
You can also incorporate seasonal fruits. Fresh blueberries in summer or dried apples in autumn work great. Customizing makes your bars fun and special for any occasion.
Storage Info
Best Ways to Store Cookie Bars
To keep your chewy monster cookie bars fresh, store them in an airtight container. This helps prevent them from drying out. You can use a plastic container or a glass jar. If you prefer, you can also wrap them tightly in plastic wrap.
When it comes to temperature, you can store them at room temperature for up to a week. If your kitchen is warm, consider refrigerating them to maintain their chewy texture.
Freezing for Longer Storage
If you want to save some cookie bars for later, freezing is a great option. First, ensure they are completely cool. Place them in a single layer on a baking sheet. Freeze them for about an hour until firm. Then, transfer them to a freezer-safe bag or container. Be sure to remove as much air as possible. This helps prevent freezer burn.
To thaw, simply take out the number of bars you want. Leave them at room temperature for about 30 minutes. You can also microwave them for a few seconds for a warm treat.
Shelf Life
When stored properly, these cookie bars can last about a week at room temperature. If refrigerated, they may stay fresh for up to two weeks. In the freezer, they can last for about three months.
Watch for signs of spoilage. If you see mold or an off smell, it’s best to discard them. A change in texture can also indicate they are no longer good. Always trust your senses when it comes to food safety.
FAQs
Can I use margarine instead of butter?
Yes, you can use margarine instead of butter. However, butter gives the best flavor. Margarine may change the texture a bit. If you choose margarine, pick a stick form for better results.
How do I know when the cookie bars are done baking?
Check the edges of the cookie bars. They should be lightly golden. The center should still look a little soft. You can also insert a toothpick. If it comes out with moist crumbs, they are ready.
Can I make these cookie bars gluten-free?
Yes, you can make these bars gluten-free. Use a gluten-free flour blend instead of all-purpose flour. Make sure the other ingredients are also gluten-free. This includes oats and chocolate chips.
What is the best way to cut cookie bars evenly?
To cut the cookie bars evenly, use a sharp knife. First, let them cool completely. Then, lightly score the top into squares. This guide helps you cut straight lines. Wipe the knife between cuts for clean edges.
How long do these cookie bars last?
These cookie bars last about one week at room temperature. Store them in an airtight container. If you want them to last longer, you can freeze them. They will keep well for up to three months in the freezer.
You’ve learned how to make delicious cookie bars. We covered ingredients, steps, and tips to get them just right. Remember, the right butter temperature and mixing technique are key for chewiness. Customize with different flavors or healthier options to fit your taste. Store them well for lasting freshness. By following these tips, you can bake cookie bars that please everyone. Enjoy your baking journey and share these treats with friends and family!