The BEST Monster Cookie Bars Recipe


– 1/2 cup btter – 3 eggs – 1 cup brown sugar – 1 cup granulated sugar – 1 1/2 cup peanut butter – 1 teaspoon vanilla – 4 1/2 cups oatmeal – 1 teaspoon salt – 2 teaspoons baking soda – 1 cup chocolate chips – 1 cup mini M&M's – 1 cup peanut butter chips


Step 1: Mix Wet Ingredients

In a mixing bowl, combine the butter, peanut butter, granulated sugar and brown sugar. Cream together using a hand or stand mixer. Add in the eggs and vanilla.

Step 2: Mix in dry ingredients

In a separate bowl, combine the oatmeal, salt and baking soda. Add in dry ingredients gradually to the wet ingredients. Fold in the M&M's, chocolate chips and peanut butter chips.

Step 3: Bake in 15" Pan

Spread batter into a 15 x 10" pan. Bake at 350 for 22-24 minutes until golden brown.

Step 4: Cut into triangles

Once cooled, cut bars into squares or triangles.


Great as an after-school snack or coffee break treat.


Store any leftovers in an airtight container at room temperature. Bars can also be frozen for later.

Check out more of our cookie bar recipes here:

M&M Cookie Bars

M&M Oatmeal Cookie Bars