Peanut Butter Brownies

Peanut butter brownies get a serious upgrade here: a one-bowl whisked batter, a generous peanut butter swirl, and a chewy, fudgy texture that holds for a full week without drying out.

These are a peanut butter-swirled riff on my chewy one-bowl brownies, developed for anyone who wants that nutty, salty contrast running through a deeply chocolatey base! They are the perfect brownies for those of us with busy lives and a constant peanut butter-chocolate craving.

Serve these alongside a scoop of vanilla bean ice cream or this chocolate ice cream recipe! There is nothing better than a warm brownie served with a large scoop of ice cream melting on top! For more peanut butter, you can make these peanut butter cup blondies next!

Ingredients & Substitutions

• Unsalted Butter: Melted butter is the fat base here, giving these brownies their dense, fudgy texture instead of a cakey crumb. Let it cool slightly before adding the eggs so you do not scramble them or seize the cocoa.
• Granulated Sugar: The high ratio of sugar to flour is what creates the glossy, crackly top and keeps the interior moist and fudgy. It also helps form that thin, meringue-like crust once the batter hits the oven just like with this fudgy brownie recipe.
• Coffee Extract: Coffee extract deepens the chocolate flavor. I am particular about my coffee extract and typically reach for Nielsen-Massey, though I have recently tried and love Watkins. If you do not have it or prefer to skip it, substitute an equal amount of vanilla extract or add 1 tablespoon of instant espresso powder to the dry ingredients instead.
• Cocoa Powder: Cocoa powder provides concentrated chocolate flavor and acts as a drying ingredient that balances the high fat and sugar content for a stable, sliceable bar. Natural or Dutch-process both work here, though Dutch-process gives a deeper color and a smoother, rounder chocolate flavor.
• Baking Powder: A small amount of baking powder keeps the brownies from feeling heavy or greasy while still maintaining a fudgy texture. Do not increase it; more leavening pushes these toward cakey.
• Smooth Peanut Butter: I use well-stirred natural peanut butter, specifically Smucker’s Natural, because it is naturally runnier and creates looser, more dramatic swirls through the batter. I love the savory contrast that simple peanuts-and-salt peanut butter brings against the sweet chocolate base. If you prefer Skippy or Jif, warm it briefly in the microwave until it loosens to a pourable consistency before swirling it in. For another recipe where that concentrated peanut butter flavor really shines, my old fashioned peanut butter cookies are worth bookmarking alongside these.

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

Variations on This Peanut Butter Brownies

• Fully Incorporated Peanut Butter. Mix the peanut butter directly into the batter along with the melted butter for a uniform peanut butter chocolate flavor throughout, rather than distinct swirls.
• Change the swirl! Change the peanut butter for Nutella, cookie butter or a high sugar seedless jam. You could also use slated caramel sauce like I do with my caramel brownie recipe!
• Add a topping. Add more peanut butter by topping these brownies with this peanut butter buttercream or you could go double chocolate with this chocolate buttercream frosting recipe! The milk chocolate ganache from these milk chocolate brownies would be divine!

Professional Tips

• Let the butter cool before adding the eggs. Hot melted butter will begin to cook the eggs on contact, giving you scrambled bits in your batter before it ever reaches the oven. The butter should feel warm to the touch, not hot.
• Do not overbake. Pull the pan at 22 to 25 minutes, when the center puffs slightly and jiggles like Jello when gently shaken just like with this brown butter brownie. The brownies will continue to set as they cool, and an overbaked brownie will be dry no matter how long you wait to slice it.
• Cool completely before slicing. The interior needs time to firm up and set after coming out of the oven. Cutting into warm brownies collapses the structure and gives you ragged, messy edges rather than clean squares.

How to Make Peanut Butter Brownies

Use these instructions to make these perfectly chewy peanut butter brownies! Further details and measurements can be found in the recipe card below.

Make Brownie Batter

Step 1: Prepare your pan and preheat the oven. Preheat to 350°F conventional (no fan). Spray a 9×13 inch pan, then line it with a strip of parchment paper that overhangs the two long sides.

Those overhang wings will act as handles when you lift the slab out later, which makes clean slicing much easier.

Step 2: Melt the butter and let it cool. Melt the butter in a large heatproof bowl, either in the microwave in 30-second bursts or set over a pot of simmering water. Set it aside while you measure your remaining ingredients. You want it warm, not hot.

Step 3: Whisk sugar into the melted butter. Add the sugar directly to the bowl of warm, melted butter and whisk vigorously until the mixture is smooth and fully combined. (photos 1 &2 Below).

If you want a fully incorporated peanut butter flavor rather than a swirl, you can stir the peanut butter directly into the batter along with the melted butter.

Step 4: Whisk in the eggs and extracts. Add the beaten eggs and extracts to the butter-sugar mixture and whisk very well.

Step 5: Add the dry ingredients and whisk to combine. Add the flour, cocoa powder, baking powder and salt to the batter and whisk until no lumps remain. Stop as soon as it is fully smooth. (photos 3 & 4).

TIP: I do whisk the dry ingredients together in a seperate bowl first because I am who I am! If your cocoa powder has any lumps, sift it before adding it to the bowl.

Step 6: Transfer the batter to the pan and add the peanut butter swirl. Pour the batter into the prepared pan and spread it into an even layer. Drop spoonfuls of peanut butter in random spots across the surface, then drag a thin offset spatula, a butter knife, or a wooden skewer through the dots in long, curving strokes to swirl. (photos 5-7).

Step 7: Bake until puffed and set. Slide the pan into the preheated oven and bake for 22 to 25 minutes. The brownies are done when the center has puffed up and the whole pan jiggles like Jello when you give it a gentle shake. That jiggle tells you the interior is set but still fudgy just like my chocolate fudge pie! Start checking at 22 minutes, since every oven runs a little differently. (photo 8).

Use the thin edge of the spatula or knife to spread the peanut butter as you drag, which gives you defined ribbons rather than muddy blobs. Natural peanut butter swirls more easily because it is already runnier; if you are using a stabilized peanut butter like Skippy or Jif, warm it briefly in the microwave first so it moves through the batter without tearing it.

Step 8: Cool completely before slicing. Let the brownies cool completely in the pan at room temperature. They will continue to set as they cool, and slicing too early gives you ragged, gooey edges rather than clean cuts.

Recipe FAQs

Before You Go

If you make these peanut butter brownies, I hope the fudgy centers and those pools of melted peanut butter butter make them impossible to share. Browse more recipes in brownies & bars recipes or make these banana brownies next!