Preheat your oven to 325°F (163°C).

In a bowl, combine the graham cracker crumbs, sugar, and melted butter. Press this mixture into the bottom of a greased baking dish to form your crust.

In another bowl, beat together the cream cheese and sugar until smooth. Add the eggs one at a time, followed by the vanilla extract and cocoa powder, until well incorporated.

Pour the cheesecake filling over the crust and bake for about 30 minutes or until set.

To prepare the ganache, heat the heavy cream until it begins to simmer. Pour it over the chopped chocolate. Let it sit for a minute, then stir until smooth.

Once the cheesecake bars are cool, pour the ganache over the top and spread evenly.