01 - Preheat oven to 350°F. Line 8x8 inch baking pan with parchment paper, allowing overhang for easy removal.
02 - Whisk melted butter and sugar in large bowl until smooth. Add eggs, vanilla, and red food coloring; whisk until fully combined.
03 - Sift flour, cocoa powder, and salt into bowl. Fold gently with spatula until just combined. Do not overmix.
04 - Reserve 1/4 cup batter. Spread remaining batter evenly in prepared pan.
05 - Beat cream cheese with sugar until smooth. Add egg and vanilla; mix until creamy.
06 - Pour cheesecake mixture over brownie batter. Smooth top evenly.
07 - Drop spoonfuls of reserved batter on cheesecake layer. Use knife to swirl gently for marbled pattern.
08 - Bake 33-36 minutes until center is just set and toothpick comes out with moist crumbs.
09 - Cool completely in pan on wire rack before lifting out and cutting into squares.