Preheat your oven to 350°F (175°C) and line an 8x8-inch baking pan with parchment paper.

In a medium bowl, whisk together melted unsalted butter and sugar until combined.

Add eggs, pure vanilla extract, and red food coloring, mixing until smooth.

Sift cocoa powder, all-purpose flour, and salt into the wet mixture, folding gently until combined.

In a separate bowl, beat softened cream cheese and sugar until creamy; mix in the egg and vanilla.

Pour three-quarters of the brownie batter into the baking pan, layer cheesecake mixture on top, and add remaining brownie batter in spoonfuls.

Gently swirl the batters together using a knife or toothpick for marbling.

Bake for 30-35 minutes, checking for doneness with a toothpick.

Allow the brownies to cool completely in the pan on a wire rack before refrigerating for at least 30 minutes.

Slice and serve with optional whipped cream or chocolate sauce.