Preheat your oven to 350°F (175°C). Line a 12-cup muffin tin with cupcake liners.
In a medium bowl, combine the melted butter, granulated sugar, cocoa powder, and salt. Mix well until smooth.
Stir in the vanilla extract, then add the eggs one at a time, mixing well after each addition.
Gradually add the flour, mixing until just combined. Be careful not to overmix.
Preparing the Cheesecake Layer:
In a separate bowl, beat the softened cream cheese and sugar until smooth and creamy.
Add the egg and vanilla extract, mixing until just combined. Again, avoid overmixing.
Assembling the Cups:
Spoon about 2 tablespoons of brownie batter into each cupcake liner.
Top each brownie layer with about 1 tablespoon of cheesecake filling.
Baking and Cooling:
Bake for 20-25 minutes, or until the edges of the brownies are set and the cheesecake layer is slightly golden.
Remove the muffin tin from the oven and let the cups cool completely in the tin.
Once cooled, transfer the loaded brownie cheesecake cups to the refrigerator and chill for at least 30 minutes before serving. This helps them set properly and enhances the flavor.