Preheat the oven to 160°C (325°F) and line a 9"x9" baking tin with baking paper.
Place the sugar and melted butter in a bowl and mix together.
Add in the vanilla extract, red food coloring and eggs and beat together.
Add in the cocoa and all purpose flour and fold them through.
Lightly fold in the white vinegar and then pour into the prepared pan and set aside to make the cheesecake filling.
Beat the cream cheese, butter, icing sugar, egg and vanilla extract together until smooth.
Pour over the cheesecake mixture and using the end of a knife, swirl that through the red velvet brownies and then place in the oven and bake for 20-25 minutes. The outside will be set and the middle will have a slight jiggle.
Allow them to cool completely before slicing and then store in the fridge in an airtight container for up to a week.
Video
Notes
If you are using red food coloring gel, use around 1 teaspoon and see how red this is. You may need to increase to up to 2 teaspoons but add this slowly as the gel is much more concentrated than liquid food coloring.
If your cocoa is lumpy, sift this into the brownie batter to avoid lumps throughout.
In the video, we sliced the brownie into a heart for Valentines day. To do this, I sliced this into 16 regular pieces and then carved a heart out of these so there were still individual pieces (albeit some odd shaped pieces)!