Monster Cookie Bars

Overhead view of sliced monster cookie bar with mini M&Ms.

5 from 3 votes

Monster Cookie Bars are filled with old fashioned oatmeal, peanut butter, chocolate chips, and mini m&ms - and make the best treats. These easy bars are quick to make and require no chill time!

Course Dessert

Cuisine American

Keyword monster cookie bars

Prep Time 15

Cook Time 25

Total Time 40

Servings bars

Calories 355kcal

Author Sue Ringsdorf

Ingredients

wet ingredients:

6 Tablespoons unsalted butter - softened
1 ¼ cup brown sugar (275 grams)
1/2 cup granulated sugar (100 grams)
2 large eggs
1 cup peanut butter (270 grams)
1 teaspoon vanilla extract

dry ingredients:

3 cups old fashioned oatmeal (240 grams)
1 ½ teaspoons baking soda
1/2 teaspoon kosher salt
¾ cup mini chocolate chips
¾ cup mini M&Ms

Instructions

Prep. Preheat your oven to 350 degrees. Prep a 9×13 pan with parchment paper, if desired. You can also just spray the pan with baking spray.
Mix wet ingredients. In a large standing mixer, cream the butter and sugars together. Add the eggs, peanut butter, and vanilla, and mix again.
6 Tablespoons unsalted butter, 1 ¼ cup brown sugar (275 grams), 1/2 cup granulated sugar (100 grams), 2 large eggs, 1 cup peanut butter (270 grams), 1 teaspoon vanilla extract
Then add the dry ingredients – the baking soda, kosher salt, and oatmeal – and mix again. Finally, fold in the chocolate chips and mini m&m's. I normally do this by hand.
3 cups old fashioned oatmeal (240 grams), 1 ½ teaspoons baking soda, 1/2 teaspoon kosher salt
¾ cup mini chocolate chips, ¾ cup mini M&Ms
Spread the cookie mixture evenly into all sides of the pan. Press down gently to get a uniform layer.
Bake for 25 minutes or to your liking. If you want them more gooey, bake for less time. Let them cool for about 10 minutes if using parchment paper (and if you want to lift them out of the pan).
Serve bars with a scoop of ice cream or with a tall glass of milk!

Notes

Storing – Place bars in an airtight container and store on the counter for three to four days.
Freezing – You can freeze these for up to two months. But I suggest either eating them or sharing them with neighbors and friends instead! I actually love sending goodies to Mike’s work and they get devoured quickly.

Nutrition