Preheat your oven to 325°F (163°C).

In a mixing bowl, combine the graham cracker crumbs, melted butter, and granulated sugar. Stir until fully combined. Press this mixture firmly into the bottom of a 9-inch springform pan. Bake for about 8-10 minutes, then remove it from the oven to cool slightly.

In a large mixing bowl, beat the softened cream cheese until smooth and fluffy. Gradually add the granulated sugar and cocoa powder, mixing well until free of lumps.

One at a time, add each egg, mixing just until incorporated. Stir in the vanilla extract and sour cream until combined.

Pour the filling into the cooled crust, smoothing the top with a spatula.

Bake in the preheated oven for about 50-60 minutes, or until the center is set but slightly wobbly. Turn off the oven and crack the oven door, allowing the cheesecake to cool for an hour inside.

Once cooled, refrigerate the cheesecake for at least 4 hours before serving.

Top with your choice of whipped cream, fresh berries, or chocolate shavings, and enjoy.