Preheat the oven to 350°F (175°C).
Prepare a muffin tin by lining it with cupcake liners.
In a mixing bowl, combine granulated sugar, cocoa powder, and melted butter.
Add eggs and vanilla extract to the mixture, stirring until well combined.
Sift in flour and mix until combined.
Divide the brownie batter evenly among the lined muffin cups, filling each about halfway.
In a separate bowl, beat together softened cream cheese, powdered sugar, and sour cream until smooth.
Spoon the cheesecake mixture over the brownie batter in each cup.
Bake in the preheated oven for 20-25 minutes.
Allow to cool completely before serving.
Top with chocolate chips or your choice of toppings before serving.