For the crust:
For the filling:
For the ganache:
1. Preheat oven to 320F (160C).
2. In a food processor, process biscuits until crumbs are formed. Add melted butter and process again until combined. press into bottom of 9-inch (23 cm) springform pan. Bake for 10 minutes. Let cool while making the filling.
3. Filling: chop the chocolate and place in a heat proof bowl. set over pot with simmering water and melt completely (you can do this step in the microwave: 20 seconds pulses until melted). Set aside.
4. In a large bowl beat cream cheese, sugar, salt and vanilla extract, beat until smooth. And sour cream and beat again until smooth. Add cocoa powder and beat again, scrape the sides of the bowl if needed.
5. Add the eggs, one at the time, beating to combine after each one. add the melted chocolate, mix until combined and smooth.
6. Wrap the bottom of the pan with aluminum foil. Pour the filling over the crust. place in a roasting pan. Place roasting pan in oven. Pour in boiling water to come halfway up side of springform pan
7. Bake for 55-60 minutes, or until center is almost set. Turn off the oven, slightly open the oven door, and allow the cake to cool in the oven for 1 hour. Remove from oven, run a thin knife around the edge of the pan, let cool to room temperature and refrigerate overnight.
8. For the ganache: chop the chocolate, place in a large bowl. In a saucepan bring the heavy cream to a simmer. Pour over the chocolate. Let sit for 1-2 minutes. Stir until smooth. Let cool slightly.
9. Pour over the cheesecake, let set and serve.