Monster Cookie Bars
Monster Cookie Bars are loaded with oats, peanut butter, chocolate chips, and M&M's and are a total crowd pleaser! They are great for a potluck, a fun after-dinner dessert, or for snacking!
Monster Cookies are one of my all-time favorite cookies, but sometimes I'm not in the mood to make a batch. I want something a little easier. Enter: Monster Cookie BARS. These bars have all of the flavors and textures of a monster cookie (I adapted this recipe from my cookie recipe), but are a lot easier because you just press the cookie dough into a baking dish and bake! Easy peasy.
Looking for other Monster cookie recipes? Check out my Monster Cookie Oat Balls and Monster Cookies!
Why You'll Love This Recipe
- Easy - this is so much easier than making Monster Cookies!
- Crowd Pleasing - these are super easy to serve to a large group of people.
Jump to:
Ingredients
Butter - I always use unsalted butter when I am baking so I can control the amount of salt in the cookies or bars.
Sugar - both granulated sugar and brown sugar are in these bars which make them sweet and chewy.
Eggs - 3 large eggs add chewiness and act as a binder in these bars.
Vanilla Extract - I pretty much always add vanilla extract to my baked goods for a hint of vanilla flavor.
Corn Syrup - this is my secret ingredient in my Monster Cookies too, and it helps keep them super chewy!
Baking Soda and Salt
Peanut Butter - I always use un-natural creamy peanut butter.
Old Fashioned Oats - also known as rolled oats, these are a must in monster cookies and give them some chewiness.
All-Purpose Flour - I always use unbleached all-purpose flour when baking.
Please refer to the recipe card for the complete list of ingredients.
Variations
Different Nut Butter - if you don't love peanut butter, you could use a different type of nut or seed butter like almond butter or cashew butter.
Festive M&M's - I love making these bars with festive M&M's around holidays, like 4th of July, Easter, Halloween, and Christmas.
Different Type of M&M's - you can switch up the type of M&M's you use, like peanut, peanut butter, crispy, and pretzel.
Different Add-Ins - instead of the add-ins recommended, you could switch it up with peanut butter chips, raisins, dried cranberries, chopped peanuts, Reese's Pieces, chopped chocolate candy, white chocolate chips, dark chocolate chips, or anything you like!
Step by Step Instructions
Photo 1. In a large bowl, beat together the melted butter, granulated sugar, and brown sugar until combined. You can do this with an electric mixer or a hand whisk.
Photo 2. Add the eggs, vanilla extract, and corn syrup, mixing until combined.
Photo 3. Add the peanut butter, and mix to combine.
Photo 4. Add the baking soda, salt, and flour, and mix to combine.
Photo 5. Add the oats, and stir to combine.
Photo 6. Add the chocolate chips, butterscotch chips, and M&M's, mixing to combine.
Photo 7. Spread the cookie dough into a greased 9x13" baking dish.
Photo 8. Bake at 325 degrees F for 25-28 minutes. The edges should be golden brown and the middle should be set. Be sure not to over-bake. Let cool and then cut into squares.
Expert Tips
Don't Over-Bake - be sure not to go over the recommended baking time. These are meany to be chewy!
Storage - store these bars covered or in an airtight container, either at room temperature or in the refrigerator.
No-Sticking - I find that just greasing my baking dish with cooking spray works to make sure these bars don't stick but if you want, you can add some parchment paper to the bottom too.
Recipe FAQs
I have not made these using quick oats and I don't think they would get the chewy texture that you will get with rolled oats.
You can make them gluten-free using gluten-free oats and gluten free one-to-one flour.
Yes! You can freeze the entire pan or cut them into bars and place them in a freezer bag. Freeze for up for 3-4 months.
Other Bar Recipes To Consider
If you make this recipe, please let me know! Leave a ⭐️⭐️⭐️⭐️⭐️ rating on this recipe below and leave a comment, or take a photo and tag me on Instagram with #greensnchocolate.
Monster Cookie Bars
Ingredients
- ½ cup unsalted butter melted
- 1 cup granulated sugar
- 1 cup brown sugar
- 3 large eggs
- 1 teaspoon pure vanilla extract
- 1 teaspoon corn syrup
- 1 teaspoon salt
- 2 teaspoon baking soda
- 1 ½ cups peanut butter creamy or crunchy, but not natural
- 2 cups old fashioned oats
- 2 cups flour
- ¾ cup butterscotch chips
- ¾ cup chocolate chips
- 1 cup M&M's
Instructions
- Preheat the oven to 325 degrees F.
- Grease 9x13" baking dish with cooking spray.
- In a large bowl with electric mixer, beat together butter and sugars with paddle attachment, or using a hand mixer.
- Add eggs, vanilla, and corn syrup, and beat until well combined.
- Add the peanut butter and beat until well combined.
- Add the salt, baking soda, and flour and mix until combined.
- Add the flour and mix until combined.
- Stir in chips and M&M's by hand. The batter will get pretty thick so use your muscles!
- Spread evenly into prepared baking pan.
- Bake in preheated oven for 25-28 minutes if using 9x13" pan or 18-22 minutes for jelly roll pan, until top is golden brown. Don't over bake!
- Let cool completely.
- Cut into squares and enjoy!
Anything with pb m&m's is a winnn! I love how gooey and delicious they look!
In the fall I did a juice cleanse for 6 days! How insane is that? I was trying to go for a week, but by day 6 I just couldn't take it anymore. I had to chew something! How did your 3 days go? Bet it felt great to bite into these delicious cookie bars when you were done : )
6 days?! That IS insane. I was so ready for food after 3 days!
Bar cookies are totally underrated! I have PLENTY of clearance easter candy that I impulse bought this morning (oops), so I am more than ready to make these!
After I saw your comment yesterday I headed straight to Target on my lunch break to raid the Easter candy sales...thanks for reminding me! 🙂
I'm a huge cookie bar fan. Regular cookies don't take that much work, but bar cookies are SO easy. They're a faster way to get a cookie fix. These bars look good!
I pretty much hate scooping out cookies, so I almost always go the cookie bar route! Plus I think they are just better and chewier that way. 😛 These look AMAZING.
You know I really don't make cookie bars anywhere near enough! I seem to forget about them I guess! These look amazing - I mean with all the oats, peanut butter chips, chocolate chips....
Even though I was in a chocolate coma this weekend, I would eat all of these.
Love cookie bars - so much faster and easier to get that much needed cookie fix. These look amazing, I love the sound of all the different chips in here - especially the pretty Easter M&M's 🙂