Peanut Butter Bars Recipe

This Peanut Butter Bars Recipe creates deeply peanut buttery bars crowned with silky milk chocolate ganache. With only 20 minutes of prep, the simple mixing method guarantees rich, chewy results!

When my husband goes out of town, I inevitably end up in a baking frenzy. These are the kind of bars my mom would have wrapped in foil for a bake sale. That’s how these bars were born—right alongside a full batch of chocolate pound cake and a tray of chocolate crickle cookies. There’s just something about peanut butter and chocolate that feels comforting and a little indulgent.

If you love that combination too, be sure to browse my easy chocolate desserts page. It’s basically a celebration of everything chocolate, including thick chocolate chip cookies—and these bars fit right in.

Ingredients & Substitutions

• Unsalted Butter: Softened butter creams more smoothly with the sugar, giving structure and lift.
• Granulated Sugar: The granulated sugar provides structure and controlled sweetness.
• Creamy Peanut Butter: Use a traditional creamy peanut butter for the most consistent texture. Natural peanut butter tends to create crumbly bars in this recipe.
• Egg + Egg Yolk: The extra yolk adds richness and keeps the bars tender.
• Vanilla Extract: Rounds out the peanut butter flavor.
• All-Purpose Flour: Just enough to hold everything together without making the bars cakey. You can replace 2 tablespoons of flour with graham cracker crumbs for a slightly sandy texture.
• Mini Reese’s Peanut Butter Cups: Add pockets of melty peanut butter and chocolate throughout.
• Milk Chocolate Chips: Mixed into the batter and used again in the ganache for a cohesive flavor, inspired by my peanut butter chocolate chip cookies.
• Heavy Cream: Melts the chocolate for a smooth ganache.

See the recipe card for full information on ingredients and quantities.

Variations on these Easy Peanut Butter Bars

• Swap the chocolate. For a deeper chocolate flavor, bake chocolate peanut butter bars using dark chocolate chips.
• Turn it into cookie bars. If you love my reeses peanut butter cookies or old-fashioned peanut butter cookies, this is the bar version of that same nostalgic flavor. You could also stir in chopped peanut butter balls for extra texture and pockets of richness.
• Make it more classic. Skip the Reese’s and lean into a simple peanut butter base—almost like a thicker, ganache-topped cousin of my scottish shortbread recipe, but with peanut butter.

How do you make this peanut butter bars recipe?

Follow these steps to bake peanut butter bars with perfectly chewy centers and golden edges every time. Further details and measurements can be found in the recipe card below.

Step 1: Preheat and prepare pan. Preheat the oven to 350°F. Line an 8-inch square baking dish with parchment paper, leaving a slight overhang for easy removal.

Step 2: Cream butter and sugar. In a large bowl, beat together softened butter and granulated sugar with an electric mixer until light and fluffy, about 2–3 minutes. Mix in the peanut butter until fully incorporated.

Step 3: Add eggs and vanilla. Beat in the egg, egg yolk, and vanilla extract until well combined and smooth.

Step 4: Mix in flour. Reduce the mixer speed to low and add the flour. Mix just until combined—do not overmix.

Step 5: Fold in mix-ins. Stir in the milk chocolate chips and mini Reese’s by hand. The batter will be thick.

Step 6: Press and bake. Press the batter evenly into the prepared baking dish. Bake in the preheated oven for 45–60 minutes, until the top is deep golden and puffed and a toothpick inserted comes out with a few moist crumbs attached.

If the batter sticks, use a piece of parchment and a rolling pin to gently level the surface.

Step 7: Cool completely. Let the bars cool fully in the pan on a wire rack before adding the ganache, about 1 hour.

Step 8: Make ganache. Place the milk chocolate chips in a heatproof bowl. Heat the heavy cream to a boil (microwave or small saucepan), then pour over the chocolate. Whisk until melted and smooth, then whisk in the softened butter.

If you prefer a slightly thicker topping, whisk in 1 tablespoon powdered sugar.

Step 9: Spread and set. Pour the ganache over the top of the peanut butter layer and spread evenly with an offset spatula. Let sit until the ganache is set, about 30–45 minutes, before slicing into 16 bars.

Recipe FAQs

Before You Go

I hope you enjoyed this rich, chewy peanut butter and chocolate treat. Be sure to check out my other delicious brownies and bars recipes next, or keep it pure peanut butter with my peanut butter cake topped with a peanut butter buttercream!