• Preheat the oven to 350°F.
• Lightly grease a 9-inch square baking pan with cooking spray, then line it with parchment paper, leaving an overhang for easy removal. Set aside.

Brownies:

• In a large microwave-safe bowl, combine the chocolate chips and butter. Melt in 30-second intervals on high heat, stirring between each interval until smooth.
• 12 ounces semi-sweet or bittersweet chocolate chips
• 6 tablespoons unsalted butter
• Stir in the sugar and vanilla extract until fully incorporated.
• ¾ cup granulated sugar
• 1 teaspoon vanilla extract
• Add the eggs one at a time, stirring after each addition until combined.
• 3 eggs
• In a separate small bowl, whisk together the cocoa powder, cornstarch, and salt.
• ¼ cup unsweetened cocoa powder
• ⅓ cup cornstarch
• ½ teaspoon salt
• Gradually add the dry ingredients to the wet mixture, stirring vigorously for one to two minutes until the batter becomes smooth and begins pulling away from the sides of the bowl.
• Fold in the mini chocolate chips.
• 1 cup mini semi-sweet chocolate chips
• Pour two-thirds of the brownie batter into the prepared pan and spread it evenly with a spatula. Set aside.
• Cheesecake Layer:
• Using a stand mixer or hand mixer, beat the softened cream cheese until light and fluffy.
• 8 ounces cream cheese, softened
• Add the sugar and continue beating until well combined.
• ½ cup granulated sugar
• Mix in the egg and vanilla extract, beating until the mixture is smooth.
• 1 egg
• ½ teaspoon vanilla extract
• Gently spoon the cheesecake mixture over the brownie layer and spread it into an even, thin layer using an offset spatula.
• Drizzle or spoon the remaining brownie batter over the top.
• Bake for 30 to 35 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs. Keep a close eye on the brownies after 30 minutes, as baking times may vary.
• Allow the brownies to cool completely in the pan. Use the parchment paper overhang to lift them out before slicing into squares.
• Store in an airtight container in the refrigerator.