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Monster Cookie Bars have all the peanut buttery, chocolatey, chewy goodness of the traditional cookie, only in super easy bar form.
I have a well-established love of bars and bar cookies.
From Peanut Butter Cookie Bars to Apple Blondies, Brownies to fruit-filled Pie Bars, and oh my heart and happy taste buds, Cheesecake Bars too – they all make me happy both because they’re absolutely delicious and they’re so very easy to make!
Salty sweet graham cracker toffee is perfect for snacking on its own or crumbling over ice cream.
Monster Cookie Bars
Bars are so much easier and quicker to make than cookies. Cookies can be finicky; they need perfect ratios of flour, sugar, and butter, or they will spread flat or won’t spread at all.
With bars, there is a lot more leeway. With sides on a pan, the dough can’t go anywhere, not to mention it saves all the time rolling, and chilling, and baking individual cookie sheets of dough.
These are just perfect for an afternoon snack with a cold glass of milk. And luckily, it only takes a few minutes to stir a batch together.
My boys absolutely love these and they’ve become a serious favorite over the years.
One hour max start to finish, even if you have to Google how to crack an egg first. What excuse do you have for not making them?
How to make Monster Cookie Bars
These soft and chewy monster bars are easy to make!
Simply cream the butter and sugars together, beat in peanut butter, eggs, and vanilla and stir in the dry ingredients.
Last of all, you’ll fold in some chocolate chips and M&Ms. Press the monster cookie dough into a 9 x 13 pan and bake.
As hard as it is to wait, try to let them cool completely before slicing them into bars.
For a few more chocolate and oatmeal dessert combinations to try, don’t miss these Cranberry White Chocolate Oatmeal Cookies and the Chocolate Revel Bars.
These Double Decker M&M Brownies from Whisking Up Yum are calling my name now too!
Monster Cookie Bars
Ingredients
- ½ cup butter softened
- 1 cup brown sugar
- ½ cup peanut butter
- 2 eggs
- 1 tsp vanilla
- 1¾ cup all purpose flour
- 1 tsp baking soda
- 1¾ cup quick cooking oats
- ¾ cup semi-sweet chocolate chips
- 1 cup M&Ms
Instructions
- Preheat oven to 350 F. Grease a 9 x 13 pan and set aside.
- In a large bowl, cream together butter and brown sugar. Beat in peanut butter, eggs and vanilla.
- In a separate bowl, stir together flour, and baking soda. Add to large bowl and stir until combined. Add oats, chocolate chips and M&Ms.
- Press into greased pan. Add additional M&Ms to the top, if desired, pressing them into the dough slightly.
- Bake for 14 – 16 minutes or until edges are slightly brown or until toothpick inserted comes out clean. Do not over bake. Let cool a bit before slicing. Letting them cool completely is best. But its almost impossible to wait that long.
Notes
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
{originally published 8/19/14 – recipe notes and photos updated 1/4/21}
These were good BUT the amount of salt is to much. It almost makes the cookie bars inedible. Next time I will reduce the amount to 1/4 tsp.
Oh my goodness, I am so sorry about that, Cari! That was a mistake in the recipe. I typically make these either with salted butter or just add a pinch of salt to the recipe. I switched over my recipe cards a while back and somehow the measurements were messed up. I’m glad they were still edible – albeit too salty!
I followed the directions and all I got was a dry flour mixture. I went over the directions three times and cannot find my mistake.
Without being in your kitchen with you, it’s hard to guess what might have gone wrong, Ana. By chance were you scooping and or shaking your flour vs spooning it into the cup and leveling it off? That’s the most common way that too much flour is added to baked goods. (And that may have created a drier dough for the recipe.)
Can I double this and bake in a jelly roll pan?
I have never tried it, but I think it would work.
Gooey & delicious! I used a 9×9 pan so I baked them for a little longer. I used peanut butter M&Ms and mini chocolate chips and these turned out great!
I’m so glad you liked them, Karissa.
Any suggestions for a substitute for egg?
Can you use sun butter instead of peanut butter?
I’ve never worked with sun butter, but if you try it, let us know how it works! Happy Baking!
What does it mean to cream the butter?
Beat them sugar and butter together with a mixer or wooden spoon until well incorporated and fluffy.
These bars are delicious! But I almost never have quick oats on hand, do you think regular rolled oats would work as well?
Yes. Rolled oats would be fine in this recipe. You could also pulse rolled oats in the blender or food processor to make quick oats.
Will steel cut oats work the same? Thanks!
Not sure. But I would stick to rolled or quick pats.
Hello, can I omit the peanut butter? Can I replace it with something else. or just leave it out all together?
These look very good! Does the oatmeal dry out the cookie bars? Thank you!
No, not at all. They are soft and delicious!