Melt together chocolate and butter in a Microwave until smooth .
To that Add Sugar and eggs ,vanilla essence and beat until its mixed well.
Seive together flour,cocoa powder and salt and add to the batter and mix well.
Add in red colour as required and vinegar and mix well.
To prepare creamcheese Mix, Beat the cream cheese until creamy then add in the sugar,vanilla essence,and eggs and beat till smoothy..
Add the brownie batter to the lined baking tray amd keep 1/4 cup of batter aside to drizzle on top later..spread the batter evenly and add in the cream cheese layer on top followed by remaining brownie batter and swirl with a knife..
Bake in a pre heated oven @180 for 35-40 minutes until top is set.
allow it to cool and slice in desired shape and serve.