This peanut butter brownies recipe has been my go-to when I want something that feels indulgent but comes together with minimal fuss. I discovered this combination one rainy weekend when I had a jar of peanut butter and a craving for deep chocolate — the swirl of peanut butter through a fudgy brownie base made each bite feel like a little revelation. The texture balances a tender, slightly gooey center with crisp edges, while the peanut butter adds a creamy, salty contrast to the rich cocoa. It’s the sort of dessert that disappears quickly at gatherings and always brings up requests for the recipe.

I particularly love making these when I need a bake-ahead dessert for potlucks or when friends drop in unexpectedly. The flavors mature a bit after a day, the peanut butter ribbons blending into the chocolate for a softer, almost ganache-like finish. If you prefer firm brownies with defined edges, bake toward the longer end of the timing; if you love gooey centers, slightly underbake and allow time to cool. These squares marry pantry-stable ingredients with one small technique — gentle mixing — that makes all the difference in texture.

Ingredients

• All-purpose flour (3/4 cup): Spoon into the measuring cup and level off with a knife to avoid packing. This keeps the crumb tender rather than dense — King Arthur or any trusted brand works well.
• Unsweetened cocoa powder (1/2 cup): Use Dutch-processed for a smoother, less acidic chocolate note, or natural cocoa for a brighter chocolate flavor.
• Baking powder (1/2 teaspoon): A small lift agent to prevent an overly dense bar; make sure it’s fresh for best rise.
• Salted butter, melted and cooled (1/2 cup): Melting butter helps ensure a fudgy texture; if you only have unsalted, add an extra 1/4 teaspoon kosher salt.
• Granulated sugar (3/4 cup) and light brown sugar (3/4 cup): The mix of white and brown keeps the bars sweet while adding moisture and a hint of caramel from the brown sugar.
• Eggs (2 extra-large): Bring to room temperature so they emulsify with the butter and sugar, which results in a more even crumb and richer mouthfeel.
• Pure vanilla extract (2 teaspoons): Adds depth and rounds out the chocolate and peanut butter flavors.
• Kosher salt (1/2 teaspoon): Balances sweetness and enhances the chocolate; use measured kosher salt, not fine table salt.
• Chocolate chips (1/2 cup): Your choice — semi-sweet for classic balance, dark for intensity, or milk for a creamier bite; fold in with dry ingredients.
• Creamy peanut butter (1 cup total): Divide 2/3 cup for dollops inside the batter and 1/3 cup to warm and drizzle for swirls. Choose a creamy, runny-style peanut butter (Jif or Skippy) for easier swirling.

Instructions

Preheat and prepare pan: Preheat the oven to 350°F. Line a 9x9-inch baking dish with parchment paper leaving an overhang on two sides to lift the bars easily. Lightly spray the parchment with nonstick cooking spray so the brownies release cleanly after baking. Combine dry ingredients: In a small bowl, whisk together 3/4 cup all-purpose flour, 1/2 cup unsweetened cocoa powder, 1/2 teaspoon baking powder, and 1/2 cup chocolate chips. Whisking breaks up any lumps in the cocoa and evenly distributes the baking powder for a uniform texture. Mix wet ingredients: In a medium bowl, add 1/2 cup melted and cooled salted butter. Stir in 3/4 cup granulated sugar, 3/4 cup light brown sugar, the two room-temperature extra-large eggs, 2 teaspoons vanilla extract, and 1/2 teaspoon kosher salt until just combined. The sugar and butter emulsify with the eggs; don’t overbeat — you want some structure but not excess air. Fold together: Gently stir the dry mixture into the wet bowl just until incorporated. Overmixing will develop gluten and make the bars tough — stop once you no longer see streaks of flour. The batter should be glossy and slightly thick. Layer the batter: Using a silicone spatula or offset spatula, spread half of the batter evenly into the prepared pan. Dollop teaspoons of 2/3 cup creamy peanut butter across the surface of the batter. These dollops create pockets of rich peanut flavor inside the bars. Top and swirl: Spread the remaining batter over the peanut butter dollops as evenly as possible. Heat the remaining 1/3 cup peanut butter in a microwave-safe bowl for about 10 seconds and stir until loosened. Drizzle the warm peanut butter over the top and use the tip of a knife to create swirls — this distributes flavor and creates the signature marbled look. Bake and test: Bake for about 30 minutes, rotating the pan halfway through if your oven runs hot. Insert a toothpick into the center — it should come out with a few moist crumbs but not wet batter. For fudgier results, remove at the earlier end of the timing; for firmer bars, add 3–5 minutes. Cool and cut: Let the brownies cool completely at room temperature for at least 2 hours so the peanut butter sets and the texture stabilizes. Lift from the pan using the parchment overhang and cut into 4 by 4 slices for 16 squares. Use a sharp knife wiped between cuts for clean edges.

Storage Tips

For short-term storage, place cooled squares in a single layer in an airtight container at room temperature for up to 48 hours. If you stack, separate layers with parchment paper. For longer storage, freeze individual squares on a parchment-lined tray for an hour, then transfer to a freezer bag or container with parchment between layers — they’ll last up to 3 months. To thaw, leave at room temperature for 30–60 minutes or warm gently in a 300°F oven for 6–8 minutes for a just-baked texture.

Ingredient Substitutions

If you don’t have salted butter, use unsalted and add an extra 1/4 teaspoon kosher salt. For gluten-free versions, substitute a 1-to-1 gluten-free baking flour and avoid cross-contamination. Swap peanut butter for sunflower seed butter to make them nut-free (note that color and flavor will change slightly). If you prefer less sugar, reduce granulated sugar to 2/3 cup and keep the brown sugar for moisture; expect a slightly less sweet but still rich bar.

Serving Suggestions

Serve slightly warm with a scoop of vanilla ice cream and a drizzle of chocolate sauce for an indulgent dessert. For a party platter, cut into smaller bite-sized squares and garnish with a light sprinkle of flaky sea salt or crushed roasted peanuts for crunch. These pair beautifully with coffee or a full-bodied milk: the bitterness of the coffee balances the sweet, while milk complements the peanut butter’s creaminess.

Cultural Background

Chocolate and peanut butter are a classic American flavor pairing, popularized in confections and sandwiches across the 20th century. The combination evokes regional favorites such as peanut butter cups and Elvis-inspired sandwiches. Swirled bars like these borrow from American home-baking traditions where layered and marbled desserts are prized for both visual appeal and textural contrast — a simple technique with roots in mid-century cookbooks and contemporary home kitchens alike.

Seasonal Adaptations

In autumn, fold in 1/2 teaspoon ground cinnamon and finish with toasted pecans for a warm, nutty twist. For summer gatherings, serve chilled squares alongside fresh berries to lighten the richness. Around the holidays, substitute half the chocolate chips with peppermint baking chips or scatter crushed candy canes on top after baking for a festive finish — allow cooling so the peppermint adheres without melting.

Meal Prep Tips

Make a double batch and freeze half for later: bake, cool, slice, freeze in a single layer, then bag. Label with the date and reheat individual squares in the microwave for 10–15 seconds or in a low oven to revive texture. If prepping for a party, bake a day ahead, keep at room temperature covered, and add fresh garnishes right before serving to maintain crisp edges and glossy swirls.

These peanut butter brownies are a small ritual of comfort — straightforward to make, endlessly shareable, and a delightful blend of texture and flavor. Try them your way and enjoy the smiles they bring.