01 - Preheat oven to 350°F. Line an 8x8 inch baking pan with parchment paper, allowing overhang on opposite sides for easy removal later.
02 - In a large bowl, whisk melted butter and sugar until smooth. Add eggs, vanilla, and red food coloring. Whisk until fully incorporated and uniform in color.
03 - Sift flour, cocoa powder, and salt directly into the wet mixture. Fold gently with a spatula until just combined, being careful not to overmix.
04 - Reserve 1/4 cup of the red velvet batter in a small bowl. Spread the remaining batter evenly in the prepared pan.
05 - In a medium bowl, beat cream cheese and sugar until completely smooth and no lumps remain. Add egg and vanilla, mixing until creamy and well combined.
06 - Pour the cheesecake mixture over the brownie batter in the pan. Use an offset spatula to spread it evenly across the surface.
07 - Drop spoonfuls of the reserved red velvet batter over the cheesecake layer. Run a knife or skewer through the batters in a figure-eight or swirling motion to create a marbled pattern.
08 - Bake for 33-36 minutes until the center is just set. A toothpick inserted in the center should emerge with a few moist crumbs, not wet batter.
09 - Let cool completely in the pan on a wire rack. Using the parchment overhang, lift the brownies out and cut into 16 equal squares.