Instructions

• Preheat the oven to 350°F (175°C). Line an 8×8-inch baking pan with parchment paper, leaving an overhang on two sides for easy removal; set the pan aside.
• Make the mint cream-cheese swirl: place 1/4 cup granulated sugar and the 1-1/2 cups (45 grams) picked mint leaves in the bowl of a food processor. Pulse until the mint is finely chopped and combined with the sugar.
• Add 8 ounces room-temperature cream cheese, 1 large room-temperature egg, and 1-1/2 tablespoons all-purpose flour to the food processor. Process until the mixture is smooth and homogeneous, stopping to scrape down the bowl if needed. Transfer the mint cream-cheese mixture to a small bowl and set aside.
• In a medium bowl, whisk together 1/2 cup plus 1 tablespoon all-purpose flour, 1/3 cup unsweetened cocoa powder, and 1/8 teaspoon kosher salt. Set the dry mixture aside.
• Prepare a double boiler: place a heatproof bowl over a pan of simmering water (do not let the bowl touch the water). Add 6 ounces dark chocolate, 1/2 cup unsalted butter, 2 tablespoons vegetable oil, 1/3 cup light brown sugar, and 1/3 cup granulated sugar to the bowl.
• Stir the chocolate-sugar-butter mixture occasionally until everything is melted, smooth, and glossy, about 5 minutes. The sugars should soften and incorporate. Remove the bowl from the heat and allow the mixture to cool slightly.
• Stir 1 teaspoon vanilla extract into the cooled chocolate mixture, then add the 3 large room-temperature eggs one at a time, whisking well after each addition until fully incorporated.
• Fold the reserved dry ingredient mixture (from step 4) into the chocolate mixture until just combined. Do not overmix.
• Transfer about 3/4 of the brownie batter to the prepared 8×8 pan and spread it into an even layer using a spatula.
• Drop spoonfuls of the mint cream-cheese mixture across the surface of the brownie batter in the pan.
• Spoon the remaining brownie batter in dollops over the mint cream-cheese dollops, covering them unevenly.
• Using a small spatula or a table knife, gently swirl the brownie batter and mint cream-cheese dollops to create a marbled pattern. Work gently so the layers remain distinct.
• Bake in the preheated oven for 30–40 minutes, or until a toothpick inserted into the center comes out with moist crumbs but not wet batter.
• Remove the pan from the oven and let the brownies cool completely in the pan on a wire rack. Once fully cooled, use the parchment overhang to lift the brownies from the pan and cut into bars.