This Peanut Butter Brookies recipe takes only 5 minutes to prepare and is my favorite way to bake two sweet treats, peanut butter cookies and brownies, at the same time in one pan.

Using a few simple shortcuts, it couldn’t be any easier to create the best bite of a chocolate brownie with a peanut butter cookie layer into a soft and sliceable square.

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Easy Peanut Butter Brookies

A Peanut Butter Brookie recipe is an easy solution when you can’t decide between two delicious desserts.

Using only a packet of peanut butter cookie mix, a box of brownie mix, Reese’s pieces, plus the traditional baking ingredients, it is so simple to make a fudge-filled brownie base topped with peanut butter cookie batter and candy.

I love the way the peanut butter cookie brownie bars rich, dark brownie perfectly balances the creamy peanut butter flavor; it’s truly the best combination of sweet and salty baked into one brookie bar.

Imagine a moist chocolate brownie baked beneath a chewy cookie – it’s the ultimate marriage of brownie meets cookie dough and Reese’s peanut butter cups or pieces and no mixer is needed.

  • Quick and easy to prepare in 5 minutes.
  • Simple shortcut recipe uses mixes plus what’s called for on the package or box.
  • Fun way to combine peanut butter cookie batter with a moist brownie.
  • Eat some now and freeze the rest for later.
  • Perfectly portable dessert for potlucks, picnics, or parties.

Other Easy Brownie Recipes

Peanut Butter Cookie Brownie Bars

Ingredients

  • Peanut butter cookie mix: You will also need the ingredients listed on the package.
  • Reese’s pieces
  • Brownie mix: You will also need the ingredients listed on the back of the box (usually water, oil, and eggs). FYI, I used the Duncan Hines brand.

Substitutions and Additions

  • More Mix-Ins: The peanut butter cookie recipe calls for Reese’s pieces in the batter, but you could swap in things like chopped nuts, peanut butter chips, or chopped peanut butter cups.
  • Brownie Base: While I love the ease and convenience of baking from a box, feel free to make homemade brownies from scratch. Some of my favorite homemade peanut butter brownie recipes include:
  • Change The Cookie: Feel free to customize your cookie/brownie combination by using your favorite flavor cookie batter. Some ideas include:
    • Brookie Bars: My other Brookie recipe uses chocolate chip cookie dough to top the brownie bottom.
    • S’moreos: Top your brownie base with a s’more sandwich.
    • Chocolate Pudding Cookies: For extra chocolate flavor, top your brownies with a chocolate cookie batter.
Peanut Butter Cookie Brownie Bars
  • Parchment Paper 
  • 7×11 casserole dish 
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How to Make Peanut Butter Brookies

  1. Prepare The Peanut Butter Cookies: Follow the package directions to prepare the cookie dough. Stir in Reese’s pieces.
  2. Make The Brownie Batter: Make the brownie batter according to the box directions and pour into a baking dish.
    Pro Tip: You may need to spread around the batter to fit edge to edge of the dish.
  3. Prepare The Pan: Add flattened cookie dough portions on top of the brownie batter. Sprinkle with Reese’s pieces.
  4. Bake: Bake at 350 degrees Fahrenheit for 35 – 40 minutes.
  5. Serve: Cool, slice, and serve. Enjoy!

Tip From Our Recipe Developer

  • Allow the cookie bars to fully cool before removing them; this makes it easier to remove them from the dish and allows them to cut better.
  • Serve this as a snack with a glass of milk or simply on their own.

Storage

  • To Store: Store cooled Brookies in a closed container at room temperature for 2-3 days. You can also store them in the fridge for 4-5 days.
  • To Freeze: You can freeze these bars in a freezer-safe container or zip loc bag for up to 3 months.
Peanut Butter Cookie Brownie Bars cut into squares

Frequently Asked Questions

Can cookie bars be frozen? 

Yes, you can freeze these cookie bars. Make sure to cut the bars first and use wax or parchment paper in between layers so the bars won’t stick together. The bars will keep for up to 3 months. Thaw completely at room temperature or in the microwave.

Can I use refrigerated peanut butter cookie dough instead?

Yes, if you can’t find or prefer not to use the dry mix, you can use refrigerated peanut butter cookie dough instead. The package used in the recipe is equal to 12 peanut butter cookies.

how will I know when my brookies are done baking?

These bars are done baking when the cookie topping is puffy and golden at the edges. You can test the brownies for doneness by inserting a toothpick in the center. If it comes out clean, the brownies are ready.

how many servings does this recipe make?

This recipe makes 9 large squares or more smaller slices.

stacked Peanut Butter Cookie Brownie Bars

Other Easy Peanut Butter & Chocolate Desserts

4.34 from 3 votes
Peanut Butter Cookie Brownie Bars featured image

Peanut Butter Brookies

Serves — 9
Peanut Butter Cookie Brownie Bars are the best bite of 2 desserts combined into one sweet treat. It is so quick and easy to make soft and chewy brownies that bake beneath peanut butter cookie batter.
Prep Time 5 minutes
Cook Time 30 minutes
Total Time 35 minutes

Ingredients
  

  • 1 7.2-ounce packet peanut butter cookie mix (plus ingredients on package)
  • ¼ cup Reese’s pieces plus more for sprinkling
  • 1 18-ounce box brownie mix (plus ingredients on package)

Instructions
 

  • Place parchment paper with high edges in a 7×11 casserole dish and preheat oven to 350F degrees.
  • Start with making your peanut butter cookies in a medium to small bowl with the ingredients on the packet.
  • Stir in ¼ cup of Reese’s pieces, reserving some to sprinkle later, and set aside.
  • Following the brownie mix directions, make your brownie batter, and pour into a 7×11 dish. Note: you may need to spread around the batter to fit edge to edge.
  • Lightly sink flattened cobblestone-like cookies into the brownie batter with the cookie dough.
  • Add any additional Reese’s pieces to the exposed brownie parts, if desired.
  • Bake for about 35-40 minutes, until the brownies come out clean but moist when a toothpick is inserted.
  • Place 7×11 dish on a wire rack. Allow the cookie bars to fully cool before removing; this makes it easier to remove them from the dish and allows them to cut better.
  • Serve on their own or with a glass of milk.

Jenn’s Notes

Storage:
  • To Store: Store cooled Brookies in a closed container at room temperature for 2-3 days. You can also store them in the fridge for 4-5 days.
  • To Freeze: You can freeze these bars in a freezer safe container or zip loc bag for up to 3 months.
Tips:
  • Allow the cookie bars to fully cool before removing; this makes it easier to remove them from the dish and allows them to cut better.
  • Serve this as a snack with a glass of milk or simply on their own.

Nutrition Info

Calories: 319kcal | Carbohydrates: 53g | Protein: 4g | Fat: 10g | Saturated Fat: 3g | Polyunsaturated Fat: 0.4g | Monounsaturated Fat: 3g | Trans Fat: 0.4g | Sodium: 326mg | Potassium: 19mg | Fiber: 1g | Sugar: 34g | Calcium: 4mg | Iron: 2mg

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4.34 from 3 votes (2 ratings without comment)

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Comments

  1. 3 stars
    Is 7×11” pan correct? My pan is almost over flowing! Should it be 9×13” took way longer than the 35-40 min