Preheat your oven to 325° F and line a muffin tray with liners.
Brownie:
In a medium sauce pan, on LOW heat, melt your butter and chocolate, stirring continuously, until both are smooth and melted.
Remove from heat and mix in sugar, vanilla and eggs - one egg at a time. Lastly stir in flour, 1/4 cup at a time, until smooth.
Reserve 1/4 cup brownie batter for the swirls.
Cream Cheese:
In a medium bowl, beat the cream cheese and sugar until smooth. Add egg and vanilla and beat until JUST combined. Don’t over mix.
Assembly:
Fill each muffin slot about half way. Then divide cheesecake batter evenly amongst the slots. Lastly top with 1/2 tsp of the reserved brownie batter on top of each to swirl with a toothpick.
Bake for 25 minutes or until a toothpick comes out mostly clean. Can have a few small crumbs on it. Allow to cool for at least 15 minutes to set. Transfer to wire rack to fully cool.
Notes
Store leftovers in a sealed container in the fridge.Add some 1/2 espresso powder to the brownie part to really enhance the chocolate flavor.