1. Preheat oven to 325 degrees. Assemble a 9-inch springform pan with the raised side of the bottom facing down.
2. In a food processor, pulse cookies until finely ground. Add butter, and pulse to moisten. Transfer to prepared pan, and press crumbs firmly and evenly into the bottom. Place pan on a rimmed baking sheet; bake 10 minutes, and set aside.
3. Wipe out bowl and blade of food processor. Add cream cheese, sugar, and salt; blend until smooth. With motor running, add eggs, then sour cream, and finally chocolate; blend filling until smooth, scraping down sides of bowl as needed.
4. Wrap bottom half of springform pan in foil. Pour in filling; place in a roasting pan. Place roasting pan in oven. Pour in boiling water to come halfway up side of springform pan. Bake just until set, 1 hour. Turn oven off, and let cheesecake sit 1 hour in oven, without opening (this helps prevent cracking).
5. Run a thin knife around the edge of the pan (this helps prevent cracking, too); leave in pan, and cool completely on wire rack. Cover loosely and refrigerate, at least 6 hours or up to overnight.
6. Prepare Chocolate Ganache. Unmold cheesecake. Spread ganache in center of cheesecake; let set before serving.
1. In a small saucepan, bring cream to a boil. Remove from heat and add chocloate. Stir until melted and then set aside until thickened 2 to 5 minutes.