Satisfy your sweet tooth with these thick and chewy Monster Cookie Bars that are packed with monster flavor! Jam-packed with chocolate and butterscotch chips, creamy peanut butter, oats, and M&Ms, this recipe will be your new family favorite!
Why you'll love this recipe
Monster Cookies are one of my favorite cookies. They're soft and chewy and full of monster flavor! I took the classic monster cookie recipe and turned it into something so much easier- Monster Cookie Bars!
There's no flour in this recipe and you won't even miss it! The oats and peanut butter hold these bars together so well that there's just no need for flour.
This easy, no-chill cookie dough is packed with a ton of mix-ins, and comes together in just one bowl.
To make the softest, chewiest, and most delicious Monster Cookie Bars, you will need:
- Butter. I use unsalted. If you use salted, you. may want to add less salt. But whichever butter you use, make sure it's softened!
- Sugar. White granulated sugar or even cane sugar will work.
- Brown sugar. You can use either light or dark brown sugar. I use whatever I have in the cupboard, so this time I used light!
- Eggs. You'll only need two!
- Vanilla extract. Try to use a good quality vanilla.
- Creamy peanut butter. Both chunky and creamy will work great in this recipe. I don't recommend using natural peanut butter, though.
- Baking soda. Make sure it's a fresh box!
- Salt. Nothing fancy- just regular table salt.
- Quick oats. I have not tried this recipe using any other type of oat.
- Chocolate chips. I use semi-sweet but you can also use milk chocolate or a combination of both.
- Butterscotch chips. A subtle mix-in that makes these bars irresistible!
- M&Ms. Use seasonal holiday colors, peanut butter filled, or even mini M&Ms for this recipe.
These Monster Cookie Bars have no flour- not because of dietary restrictions, but because they just don't need it!
If you're on a gluten-free diet, please make sure that your oats are certified gluten-free.
Begin this recipe by preheating your oven to 350 degrees F. Lightly grease a 9x13 cake pan and set it aside.
Use softened butter, shortening, or cooking spray to grease the pan.
In a large mixing bowl, cream together the softened butter, sugar, and brown sugar. Using a hand mixer, beat in the eggs one at a time, mixing after each addition.
Mix in the vanilla extract, creamy peanut butter, baking soda, and salt. Beat until combined.
With a wooden spoon or spatula, stir in the quick oats, chocolate chips, butterscotch chips, and M&Ms. Reserve some of the M&Ms for the top of the bars if you desire.
Transfer the cookie dough to the prepared cake pan and spread it out. Sprinkle on the reserved M&Ms and press them firmly into the dough.
Bake the cookie bars for 18 to 20 minutes at 350 degrees F, or until the edges are lightly browned. Let the pan cool on a wire rack and then cut them into bars.
Tips & tricks
Make sure the butter is room temperature. Creaming the butter, sugar, and brown sugar will be a lot easier if the butter is softened. If the butter isn't soft, the cookie dough may have small chunks of butter and won't be as smooth.
Use chunky peanut butter. For this recipe, I use creamy peanut butter because it's what I always have on hand. Add a little crunch and use chunky peanut butter! I don't recommend using natural peanut butter.
Don't over bake the bars. Just like regular cookies, these bars can easily be over baked. The edges should be lightly browned and the center will still be very soft until it has time to set.
- Mixing Bowl Set. Find the perfect size in my favorite mixing bowl set.
- Hand Mixer. Easily cream together the butter and sugars with this handy mixer.
- Spatula. Use a silicone spatula so scrape the bowl clean and easily press the cookie dough into the cake pan.
Store your leftover cookie bars in an airtight container on the counter for up to three days.
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Monster Cookie Bars
- 6 tablespoon unsalted butter softened
- 1 c sugar
- ¾ c brown sugar
- 2 eggs
- ½ teaspoon vanilla extract
- 9 oz creamy peanut butter
- 1 ½ teaspoon baking soda
- ½ teaspoon salt
- 2 ½ c quick oats
- ½ c chocolate chips
- ½ c butterscotch chips
- ½ c M&Ms
- Preheat your oven to 350°F. Lightly grease a 9x13 cake pan.
- In a large bowl, cream together the butter, sugar, and brown sugar with a hand mixer. Beat in the eggs, one at a time, mixing after each addition.
- Add in the vanilla extract, peanut butter, baking soda, and salt. Beat until combined.
- With a wooden spoon or spatula, stir in the oats, chocolate chips, butterscotch chips, and M&Ms (reserve some for the top of the bars if desired).
- Transfer the cookie dough to the prepared cake pan and spread it out. Sprinkle on reserved M&Ms and press them into the dough.
- Bake for 18 to 20 minutes, or until the edges are lightly browned.
- Let cool on a wire rack and cut into bars.
The nutritional information provided is only an estimate. For accurate results, we recommend calculating the nutritional information based on the ingredients and brands you use.
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