01 -
Heat oven to 350°F. Line 8-inch square pan with parchment, grease with butter.
02 -
Combine melted butter, sugar, cocoa, vanilla, food coloring, salt, and vinegar.
03 -
Whisk eggs separately, then mix into batter. Fold in flour until just combined.
04 -
Spread brownie batter in pan, reserve 1/4 cup for topping.
05 -
Beat cream cheese, sugar, vanilla and egg yolk until smooth.
06 -
Spread cream cheese mixture over brownie batter. Drop reserved batter on top.
07 -
Use knife or toothpick to swirl batters together.
08 -
Bake 30 minutes. Cool completely before cutting.