**Prepare the Crust:** Preheat the oven to 325°F (160°C). In a mixing bowl, combine the chocolate cookie crumbs, melted butter, and sugar until evenly mixed. Press about 1 tablespoon of the mixture into the bottom of each lined muffin tin. Bake for 5 minutes, then set aside to cool.

**Make the Filling:** In a large bowl, beat the cream cheese and sugar until smooth. Add the egg and mix until fully incorporated. Stir in the heavy cream, melted chocolate, and vanilla extract until the mixture is creamy and uniform.

**Bake the Cheesecakes:** Divide the filling evenly among the prepared crusts, filling each about 3/4 full. Bake for 15–18 minutes or until the centers are just set but still slightly jiggly. Remove from the oven and let cool to room temperature, then refrigerate for at least 2 hours.

**Prepare the Ganache:** In a double boiler or microwave-safe bowl, heat the chopped chocolate and heavy cream together until smooth and glossy. Stir until fully combined.

**Assemble the Cheesecakes:** Spoon or pour the ganache over each chilled cheesecake, spreading it evenly. Add garnishes like white chocolate shavings or berries if desired. Chill for another 30 minutes to set the ganache.

**Serve:** Carefully remove the cheesecakes from the liners or pan and serve chilled.