Preheat your oven to 325°F (160°C) and line a 12-cup muffin tin with paper liners.

In a mixing bowl, combine melted butter, sugar, and cocoa powder until smooth.

Add vanilla extract and eggs to the mixture, whisking until fully incorporated.

Fold in flour and salt until a thick brownie batter forms.

Divide the brownie batter evenly among the muffin cups, filling each about halfway.

In a separate bowl, beat the cream cheese and sugar until smooth and creamy.

Add the egg and vanilla extract to the cream cheese mixture and beat until fully combined.

Spoon the cheesecake mixture on top of the brownie batter in each muffin cup, filling almost to the top.

Bake in the preheated oven for 20-25 minutes, or until the cheesecake layer is set and a toothpick inserted into the brownie layer comes out with a few moist crumbs.

Let the cheesecake bites cool completely in the pan, then transfer to the refrigerator to chill for at least 2 hours before serving.