If you love the idea of chocolate-and-peanut-butter candy but want it in bar form, these Buckeye Brownies are for you. They start with a fudgy brownie base, get a thick, spreadable peanut butter middle, and finish with a glossy chocolate ganache. The result cuts like a candy bar but feeds a crowd.
I make these when I need something that travels well and stores beautifully. They’re straightforward to assemble and forgiving in the ways that matter: bake time, spreading the peanut butter layer, and the final ganache set-up. You don’t need special skills—just a few tools and some patience while layers cool and set.
Below I lay out exactly what I use, the full step-by-step directions, helpful swaps, and troubleshooting notes that have saved me from runny peanut butter layers and grainy ganache. If you follow the steps and measurements here, you’ll have clean slices and that classic buckeye flavor everyone asks about.
What We’re Using
This recipe relies on pantry-stable ingredients and a small set of equipment. Read through the ingredients and steps before you start so everything is at hand—especially the melted butter and cooling times.
Ingredients
- ½ cup (113 g) unsalted butter, melted and cooled — provides fat for richness and helps create a fudgy crumb.
- 1 cup (200 g) granulated sugar — adds sweetness and structure to the brownie base.
- ¾ cup (150 g) light brown sugar — contributes moisture and a subtle caramel note to the brownies.
- 3 large eggs — bind the batter and add lift and texture.
- 1 teaspoon (5 ml) pure vanilla extract — enhances overall flavor; use good-quality vanilla if possible.
- ½ teaspoon salt — balances sweetness and accentuates chocolate and peanut flavors.
- ¾ cup (60 g) cocoa powder — unsweetened; gives the brownies a deep chocolate flavor.
- ¾ cup (90 g) all-purpose flour — provides structure; do not overmix once added.
- 1 ½ cups (360 g) smooth peanut butter — the core of the peanut butter layer; smooth gives the classic texture.
- ½ cup (113 g) unsalted butter — melted into the peanut butter for spreadability and richness.
- 2 ½ cups (300 g) powdered sugar — sweetens and thickens the peanut butter layer to a spreadable consistency.
- 1–2 tablespoons milk — used to adjust the peanut butter filling to a smooth, spreadable consistency.
- ¾ cup (180 ml) heavy cream — makes the ganache smooth and glossy when poured over the peanut butter layer.
- 1 ½ cup (255 g) semi-sweet chocolate chips — will be melted into the hot cream to form the ganache.
Buckeye Brownies, Made Easy
- Preheat the oven to 350°F (180°C) or 160°C for a fan oven. Grease and line a 9×13-inch (approx. 23×33 cm) baking pan with parchment paper, leaving some overhang for easy removal.
- In a large bowl, whisk together the melted and cooled ½ cup (113 g) unsalted butter, 1 cup (200 g) granulated sugar, and ¾ cup (150 g) light brown sugar until smooth.
- Add 3 large eggs, 1 teaspoon (5 ml) pure vanilla extract, and ½ teaspoon salt to the butter-sugar mixture. Whisk until fully combined.
- Add ¾ cup (60 g) cocoa powder and ¾ cup (90 g) all-purpose flour. Stir with a spatula or spoon until no dry streaks remain and the batter is uniform.
- Pour the batter into the prepared pan and smooth the top into an even layer. Bake in the preheated oven for 18–20 minutes, or until a toothpick inserted near the center comes out with a few moist crumbs.
- Remove the brownies from the oven and let them cool completely in the pan on a wire rack.
- While the brownies cool, make the peanut butter layer: in a medium microwave-safe bowl combine 1½ cups (360 g) smooth peanut butter and ½ cup (113 g) unsalted butter. Microwave in 30-second intervals, stirring well after each interval, until the mixture is smooth and pourable.
- Add 2½ cups (300 g) powdered sugar to the peanut butter mixture and mix until combined; the mixture will be stiff. Add 1–2 tablespoons milk, a little at a time, until the mixture becomes smooth and spreadable.
- Spread the peanut butter mixture evenly over the cooled brownies, smoothing to the edges.
- Make the ganache: heat ¾ cup (180 ml) heavy cream until steaming (do not let it boil). Pour the hot cream over 1½ cups (255 g) semi-sweet chocolate chips in a heatproof bowl and let sit for 3 minutes. Stir until the chocolate is fully melted and the mixture is smooth.
- Pour and spread the ganache evenly over the peanut butter layer. Refrigerate for at least 1 hour to set before using the parchment overhang to lift the slab from the pan and slice.
Why I Love This Recipe
It hits three textures in one bar: a slightly crackly top brownie crust, a dense peanut butter middle, and a silky ganache finish. That contrast is what makes every bite interesting. It’s also a great make-ahead dessert—set in the fridge, it firms up and slices cleanly the next day.
The method is unfussy. Melt butter, whisk sugars and eggs, fold in dry ingredients, and bake. While the brownies cool, you handle the peanut butter layer and ganache; everything has its moment so you’re not juggling steps. That pacing makes it a reliable choice for parties.
Ingredient Flex Options
- Peanut butter — the recipe calls for smooth peanut butter for that classic texture. If you prefer some bite, you can use natural or crunchy, but expect a slightly different spreadability.
- Chocolate chips — semi-sweet chips are listed; if you want a richer top, swap for dark chocolate chips, or use milk chocolate for a sweeter finish.
- Milk — the 1–2 tablespoons milk tunes spreadability. Use whole milk for creamier results; plant-based milk can work but may affect set time.
Cook’s Kit
- 9×13-inch baking pan — this is sized for the recipe; lining with parchment with overhang makes lifting and slicing simple.
- Mixing bowls — at least one large for the batter and one medium for the peanut butter mixture.
- Spatula and whisk — a whisk for the wet mix, spatula for folding and spreading.
- Wire rack — allow the brownies to cool completely before adding the peanut butter layer.
- Heatproof bowl — for making ganache when combining hot cream and chocolate chips.
Troubleshooting Tips
Batter and Bake
If your brownie batter seems very thin, check that your melted butter cooled slightly before adding eggs—hot butter can alter texture. The bake time is short; check at 18 minutes. A toothpick should come out with a few moist crumbs. Overbaking will produce drier brownies that don’t pair as well with the peanut butter layer.
Peanut Butter Layer
If the peanut butter layer is too stiff after adding powdered sugar, add the milk a teaspoon at a time until you reach a smooth, spreadable consistency. If it’s too thin, add a bit more powdered sugar, but avoid adding too much or the layer will be crumbly.
Ganache Issues
If the ganache appears grainy after stirring, it may have been overheated or chocolate wasn’t fully melted. Warm it gently over a double boiler while stirring until smooth. If it becomes too thin, let it cool slightly before pouring so it doesn’t run off the edges of the peanut butter layer.
Year-Round Variations
These bars adapt well to seasons and holidays. For a winter twist, stir a pinch of cinnamon into the peanut butter layer. For summer gatherings, top the ganache with chopped roasted peanuts or a sprinkle of flaky sea salt for a sophisticated finish. Around Valentine’s Day, add a few drops of espresso to the ganache for depth and serve with fresh berries.
Notes on Ingredients
The recipe’s balance depends on two things: the peanut butter layer’s firmness and the ganache’s gloss. Using the exact powdered sugar and peanut butter quantities listed gives the intended texture; adjust milk sparingly. Use semi-sweet chips as called for unless you want to significantly change the sweetness.
The unsalted butter is used twice—once in the brownie batter and again in the peanut butter layer—so the ½ teaspoon salt in the batter is important to balance flavor without making the bars overly salty.
Prep Ahead & Store
Make Ahead
You can bake the brownies a day ahead and keep them in the pan, covered, until ready to assemble the peanut butter and ganache layers. After assembly, chill for at least an hour to set, then slice. For parties, I often make them the day before so flavors meld and slicing is neater.
Storage
Store finished Buckeye Brownies in an airtight container in the refrigerator for up to 5 days. For longer storage, freeze slices flat in layers separated by parchment for up to 2 months; thaw in the refrigerator before serving. The ganache may lose a little shine after freezing but the flavor holds up well.
Your Questions, Answered
Q: Can I use natural peanut butter? A: Yes, but it often separates; stir it well before measuring and note that natural peanut butter can change spreadability. You may need a touch more powdered sugar.
Q: Can I skip chilling? A: Chilling firms the layers for clean cuts. If you skip chilling, the ganache and peanut butter can be softer and messier to slice.
Q: How do I get clean slices? A: Warm a sharp knife under hot water, wipe dry, and slice in single, decisive strokes. Wipe the blade between cuts.
The Last Word
These Buckeye Brownies are a reliable, crowd-pleasing dessert that feels like a treat but comes together with ordinary kitchen tools. Follow the steps in order, give the layers time to cool and set, and don’t rush the ganache. You’ll end up with bars that look and taste like something special with a texture for everyone to love.
Make them for gatherings or keep a pan in the fridge for when you want a serious chocolate-and-peanut-butter fix. They store well, travel well, and—best of all—people will ask you for the recipe.
Buckeye Brownies
Ingredients
Ingredients
- ?1/2 cup 113 gunsalted buttermelted and cooled
- ?1 cup 200 ggranulated sugar
- ?3/4 cup 150 glight brown sugar
- ?3 largeeggs
- ?1 teaspoon 5 mlpure vanilla extract
- ?1/2 teaspoonsalt
- ?3/4 cup 60 gcocoa powder
- ?3/4 cup 90 gall-purpose flour
- ?1 1/2 cups 360 gsmooth peanut butter
- ?1/2 cup 113 gunsalted butter
- ?2 1/2 cups 300 gpowdered sugar
- ?1-2 tablespoonsmilk
- ?3/4 cup 180 mlheavy cream
- ?1 1/2 cup 255 gsemi-sweet chocolate chips
Instructions
Instructions
- Preheat the oven to 350°F (180°C) or 160°C for a fan oven. Grease and line a 9×13-inch (approx. 23×33 cm) baking pan with parchment paper, leaving some overhang for easy removal.
- In a large bowl, whisk together the melted and cooled ½ cup (113 g) unsalted butter, 1 cup (200 g) granulated sugar, and ¾ cup (150 g) light brown sugar until smooth.
- Add 3 large eggs, 1 teaspoon (5 ml) pure vanilla extract, and ½ teaspoon salt to the butter-sugar mixture. Whisk until fully combined.
- Add ¾ cup (60 g) cocoa powder and ¾ cup (90 g) all-purpose flour. Stir with a spatula or spoon until no dry streaks remain and the batter is uniform.
- Pour the batter into the prepared pan and smooth the top into an even layer. Bake in the preheated oven for 18–20 minutes, or until a toothpick inserted near the center comes out with a few moist crumbs.
- Remove the brownies from the oven and let them cool completely in the pan on a wire rack.
- While the brownies cool, make the peanut butter layer: in a medium microwave-safe bowl combine 1½ cups (360 g) smooth peanut butter and ½ cup (113 g) unsalted butter. Microwave in 30-second intervals, stirring well after each interval, until the mixture is smooth and pourable.
- Add 2½ cups (300 g) powdered sugar to the peanut butter mixture and mix until combined; the mixture will be stiff. Add 1–2 tablespoons milk, a little at a time, until the mixture becomes smooth and spreadable.
- Spread the peanut butter mixture evenly over the cooled brownies, smoothing to the edges.
- Make the ganache: heat ¾ cup (180 ml) heavy cream until steaming (do not let it boil). Pour the hot cream over 1½ cups (255 g) semi-sweet chocolate chips in a heatproof bowl and let sit for 3 minutes. Stir until the chocolate is fully melted and the mixture is smooth.
- Pour and spread the ganache evenly over the peanut butter layer. Refrigerate for at least 1 hour to set before using the parchment overhang to lift the slab from the pan and slice.
Equipment
- 13 x 9 inch baking pan
- Mixing Bowl
- Offset Spatula
Notes
Try an offset spatula.This handy tool makes spreading the brownie batter, peanut butter filling, and chocolate ganache evenly super easy.
Cut clean squares.Chill the bars down completely, then remove them from the pan. Cut the bars using a large knife that you’ve run under hot water. Clean the knife with the hot water between each cut.
To Store:Keep in an airtight container at room temperature for up to 3 days.
