01 -
Heat your oven to 350°F. Line an 8x8 baking pan with parchment paper or give it a good spray with non-stick spray.
02 -
Stir together melted butter and sugar until the mixture looks smooth. Toss in the eggs, vanilla, food coloring, and vinegar, and mix. Add the cocoa, flour, and salt last after sifting. Save about 1/4 cup of batter for later.
03 -
Blend softened cream cheese with sugar until creamy. Mix in the egg and vanilla until smooth and lump-free.
04 -
Spread the red velvet mixture into the prepared pan. Pour the cream cheese layer on top. Create swirls by mixing the two layers together. Add dabs of the reserved red velvet batter and swirl once more for a marbled look.
05 -
Cook for 25-30 minutes. It's done when the middle feels firm, and a toothpick comes out with a few sticky crumbs. Let it cool completely before cutting.