These rich chocolate buckeye brownies are filled with 3 delicious layers of chocolate and peanut butter. The easiest chocolate peanut butter brownies using brownie mix!

Buckeye brownie with a bite taken out showing the peanut butter and chocolate ganache layers.

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Easy Buckeye Brownies with Brownie Mix

I lived in Ohio for a short time, and let me tell you, the buckeye obsession is completely real. If you love chocolate peanut butter balls, I know you get it! These buckeye brownies are my way of bringing that same comfort food flavor home, but in a chewy decadent brownie.

These brownies pack three incredible layers: a fudgy boxed brownie base, a creamy peanut butter filling, and a smooth chocolate ganache on top. If you love my buckeye cupcakes or buckeye bark, these are going to be your new favorite.

XO - Jamielyn

Ingredient Notes

Here is what you need for the layers!

  • Brownies: I used a boxed brownie mix. Look for one that you make in a 9×13 pan. My favorite boxed brand is Ghiradelli. You will also need all ingredients on the back of the box.
  • Peanut butter filling: Creamy peanut butter, butter, powdered sugar, brown sugar and vanilla.
  • Ganache: I used milk chocolate chips but you can use dark chocolate chips or semi-sweet chocolate chips and melted butter.
Mixing boxed brownie batter with a wooden spoon in a glass bowl.

How to Make Buckeye Brownies

Start with your box of brownies. Mix everything according to the package directions, pour it into your prepared pan, and bake at 350°F.

This is the easy part, and honestly, using a box mix here is the right call. It gives you that perfect fudgy base every time without any guesswork.

Spreading creamy peanut butter filling over a baked brownie layer in a 9x13 pan.

While the brownies cool completely, make your peanut butter filling. Cream together the softened butter, peanut butter, and vanilla, then mix in the brown sugar and slowly beat in the powdered sugar.

This layer is so good I have to stop myself from eating it straight from the bowl. Spread it over the cooled brownies with a spatula and take your time getting it even.

Stack of buckeye brownies on a white plate showing three layers of brownie, peanut butter, and chocolate ganache.

The chocolate ganache on top is what really brings it all together. Melt your chocolate chips and butter in the microwave, stirring every 30 seconds until it’s completely smooth, then pour it right over the peanut butter layer.

Spread it to the edges and pop the whole pan in the fridge for about 30 minutes until the chocolate sets. Worth every minute of the wait.

Recipe Tips

  • Line your 9×13″ pan with foil or parchment and grease it well. Skipping this step is a mistake you’ll only make once.
  • If the peanut butter frosting gets too thick, add a small splash of milk or heavy cream to loosen it up.
  • Want to go all in? Use a homemade brownie as the base instead of box mix.
  • The ganache can seize up if overheated. Melt at 50% power and stir every 30 seconds. If it still gives you trouble, swap the butter for heavy cream instead for a smoother result.
  • These are best eaten cold straight from the fridge with a big glass of milk.
Close up of a buckeye brownie with a bite taken out revealing the peanut butter and chocolate ganache layers.

Love brownies? Try these copycat cosmic brownies, cake mix brownies and Nutella brownies, too!

More Brownie Recipes

Buckeye brownie with a bite taken out showing the peanut butter and chocolate ganache layers.

Buckeye Brownies Recipe

4.89 from 9 votes
Recipe by: Jamielyn Nye
Prep Time: 20 minutes
Cook Time: 30 minutes
Total Time: 50 minutes
Servings: 24
These rich chocolate buckeye brownies are filled with 3 delicious layers of chocolate and peanut butter. The easiest chocolate peanut butter brownies using brownie mix!
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Ingredients 

Brownie Base:

  • 1 box brownie mix , plus ingredients on box (use a box mix that calls for a 9×13" pan)

Peanut Butter Layer:

  • ½ cup unsalted butter , softened
  • ¾ cup creamy peanut butter
  • 1 teaspoon vanilla extract
  • ¼ cup light brown sugar
  • 1 ¾ cups powdered sugar , more as needed
  • milk , as needed to thin out mixture

Chocolate Glaze:

  • 1 ½ cups semi-sweet chocolate
  • ⅓ cup heavy cream

Instructions

Brownies:

  • Preheat oven to 350°F. Line a 9×13" pan with parchment paper or foil and lightly grease with non-stick cooking spray.
  • Mix brownie mix with ingredients listed on package, then pour in pan and bake according to directions on the box. Allow to cool completely.

Peanut Butter Layer:

  • In a large bowl, mix together 1/2 cup butter, 3/4 cup peanut butter and 1 teaspoon vanilla. Add in 1/4 cup brown sugar. Slowly beat in 1 3/4 cups powdered sugar. If it's too thin, add another Tablespoon of powdered sugar. If it gets too thick, add a splash of milk.
  • Add small scoops evenly over the brownie layer. Then gently press down with a spatula.

Chocolate Ganache:

  • For the ganache, add 1 1/2 chocolate chips and 1/3 cup heavy cream to a microwave-safe bowl. Microwave for 1 minute, then stir until smooth. Pour over the peanut butter layer and spread evenly. Refrigerate brownies for 20 minutes or until glaze is set.
  • Once chocolate has set, slice brownies with a plastic knife (trust me it works best).

Last step: Please leave a comment and rating after you make the recipe.

Notes

Storage: Keep leftovers in an airtight container in the refrigerator for up to 5 days. Serve cold or let them come to room temperature before eating.
Freezer: Flash freeze brownies first, then transfer to a freezer-safe container or wrap individually in plastic wrap for up to 3 months.

Nutrition

Calories: 221kcal, Carbohydrates: 24g, Protein: 3g, Fat: 12g, Saturated Fat: 5g, Cholesterol: 14mg, Sodium: 116mg, Potassium: 55mg, Sugar: 17g, Vitamin A: 175IU, Calcium: 11mg, Iron: 0.8mg

Nutrition provided is an estimate. It will vary based on specific ingredients used.