Frosted Peanut Butter Cookie Bars

Do bakers like me (read: people who usually do everything, and I mean everything, from scratch) use mixes sometimes? Absolutely. Today I discovered a bag of peanut butter cookie mix in my pantry and decided to whip up some frosted peanut butter cookie bars with it.

While scratch baking is great if you have the time and inclination, many people are just too busy to go about softening butter and whisking eggs and whatnot. Enter the bag, or boxed, mix: a convenient way to have home-baked treats in no time. You can always jazz up a boxed mix, which is what I did here; I added a scratch-made peanut butter frosting to these bars, but you could just as easily use a can of chocolate or vanilla frosting from the grocery store if you like. I sprinkled half of these bars, which Mike will take to work, with some chocolate chips once they were frosted, too.


  • 1 box or bag peanut butter cookie mix, plus the ingredients listed on the box/bag
  • 8 tablespoons butter
  • 1 cup smooth peanut butter
  • 2 cups powdered sugar
  • 1 tablespoon vanilla extract


Preheat oven to 350 degrees.

Prepare your cookie mix according to the package directions; I used Betty Crocker peanut butter cookie mix, which called for three tablespoons of vegetable oil, one tablespoon of water, and one egg. Mix dough and press into an ungreased 9 x 13 baking pan; bake for 18 minutes, until the top is just golden and a toothpick inserted in the center comes out clean.

Cool bars completely before frosting; to make frosting, beat butter and peanut butter in a mixer for 2-3 minutes until smooth and nearly all the lumps of butter have disappeared. Add powdered sugar and vanilla, beating on low, then medium, then high speed for about 3-4 minute total.

Spread frosting over cooled bars; if desired, sprinkle with chocolate chips. Cut into bars; makes 21-24 bars, depending on how large you cut them.


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