Preheat the oven to 325°F (160°C).
Prepare the crust by mixing graham cracker crumbs, cocoa powder, sugar, and melted butter in a bowl.
Press the mixture into the bottom of a muffin tin lined with paper liners.
Bake the crust for 8-10 minutes until set.
In a mixing bowl, beat the softened cream cheese until smooth.
Add powdered sugar, vanilla, and mix until well combined.
Stir in the eggs, one at a time, mixing just until incorporated.
Fold in the semi-sweet chocolate chips and pour the filling over the baked crust.
Bake for another 20-25 minutes, or until the center is set.
Allow the mini cheesecakes to cool completely before refrigerating for at least 4 hours.