Triple Peanut Butter Monster Cookie Bars

A stack of the peanut butter monster cookie bars

Triple Peanut Butter Monster Cookie Bars

Triple Peanut Butter Monster Cookie Bars are loaded with peanut butter, peanut butter chips, mini reese's pieces, and oatmeal! This recipe makes an entire cookie sheet of cookie bars & they freeze perfectly.

Course Dessert

Cuisine American

Keyword peanut butter monster cookie bars, sheet pan monster cookie bars

Prep Time 15

Cook Time 15

Cooling Time 30

Total Time 1

Servings

Calories 216kcal

Equipment

Ingredients

1/2 cup (1 stick) salted butter softened
1½ cups creamy peanut butter
1 cup light brown sugar
1 cup granulated sugar
3 large eggs
1 tablespoon vanilla extract
3 cups old-fashioned oats
1½ cups quick oats
1 teaspoon baking soda
1 bag (9.9 oz) Reese's Pieces (or Mini Reese's Pieces)
1 cup peanut butter chips

Instructions

Heat the oven to 350° F. Prepare a cookie sheet (12" x 18") and spray it with cooking spray or line with parchment paper. Set aside.
^{*I use a pre-cut piece of parchment paper because I think parchment paper helps the bars cook more evenly and prevents the bottoms from over browning.}
In a large mixing bowl using an electric mixer, or use a stand mixer with the paddle attachment, beat the butter, peanut butter, light brown sugar, and granulated sugar on medium speed until it's combined well, creamy, and fluffy looking. About 2-3 minutes.
^{*It's important to beat at least 2 minutes. You want the creamed mixture to be very pale in color and fluffy looking.}
1/2 cup (1 stick) salted butter, 1½ cups creamy peanut butter, 1 cup light brown sugar, 1 cup granulated sugar
Add in the eggs and vanilla extract and beat on medium speed until combined.
3 large eggs, 1 tablespoon vanilla extract
Add in the old-fashioned oats, quick oats, and baking soda. Beat until everything is thoroughly mixed together.
3 cups old-fashioned oats, 1½ cups quick oats, 1 teaspoon baking soda
Add in the Reese's Pieces and peanut butter chips, and beat until they're combined well in the cookie dough.
^{*If wanted, reserve some of each to press on top of the bars before baking. This is optional. Just makes them look pretty.}
1 bag (9.9 oz) Reese's Pieces, 1 cup peanut butter chips
Dump the monster cookie bar dough onto the prepared cookie sheet and spread it out with your clean hands, wooden spoon, or spatula.
^{*Gently press the reserved Reese's Pieces and peanut butter chips onto the top of the bars, if using.}
Bake for 16-20 minutes. The edges should be lightly golden brown while the middle should still look somewhat pale and slightly underdone.
^{*It's important to not overbake the bars. They will continue cooking and setting as they cool. I always bake for the minimum time.}
Remove the cookie sheet from the oven and let it cool, at room temperature, for 30 minutes to 1 hour so the bars can cool down, firm up, and continue cooking slightly.
Cut into squares using a pizza cutter (makes it so easy) and enjoy! These can be eaten warm or cooled to room temperature.

Notes

Peanut Butter : Do not use 'all-natural' peanut butter or peanut butter with a thick oil layer on top in this recipe. For best results, and texture of cookie bars, use regular classic creamy peanut butter. I have found that the all-natural peanut butter tend to dry out baked goods and make the texture drier.

I love freezing extra bars because this recipe makes a lot! Wrap one or two bars in plastic wrap, and then place the wrapped bars inside a freezer-safe container or Ziploc bag. Eat them chilled, let them sit at room temperature for a bit, or warm it up in the microwave.

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