Preparation Steps

• Preheat your oven to 350°F (175°C). Line a 9x9-inch baking pan with aluminum foil, leaving an overhang on the sides for easy removal, and lightly spray with cooking spray.
• In a large, microwave-safe bowl, combine the unsweetened baking chocolate and 0.75 cup unsalted butter. Heat on HIGH power for 2-3 minutes, stirring every 30 seconds, until the chocolate is completely smooth and melted.
• Stir the granulated sugar into the melted chocolate mixture until well combined. Add the eggs, 1 teaspoon vanilla extract, and Dutch-process cocoa powder, stirring well until smooth.
• Gently fold in the all-purpose flour with a spatula until just combined. Do not overmix. Spread the brownie batter evenly into the prepared baking pan.
• In a separate small bowl, combine the creamy peanut butter, 2 tablespoons melted unsalted butter, powdered sugar, and 1 teaspoon vanilla extract. Stir until the mixture is smooth and well combined.
• Drop spoonfuls of the peanut butter mixture on top of the brownie batter. Using a butter knife or the back of a wooden spoon, gently swirl the peanut butter through the brownie batter to create a marbled effect.
• Bake for 28-35 minutes, or until the edges are set and a toothpick inserted into the center comes out with moist crumbs, but not wet batter.
• Let the brownies cool completely in the pan before lifting them out by the foil overhang and cutting them into squares. This ensures clean cuts and a fudgy texture.