For the brownie batter, melt the chocolate and butter together. Mix with sugar, eggs and vanilla thoroughly. Add in the flour and salt. Save 1 cup of the brownie batter. Pour the remaining batter into a parchment lined pan - 8 x 8, or equivalent. Beat together cream cheese, sugar and egg. Pour mixture over brownies. Spoon reserved brownie batter in dollops on top and run designs with a toothpick. Bake at 350 for about 30 minutes. Let cool 20 minutes, wrap in plastic wrap and refrigerate to cool about a hour before cutting, enjoy!