Butter a removable bottom pan (9 – 10 in/20 -22 cm). Place chocolate wafers, sugar, pinch of cinnamon and the melted butter and process until blended. Press mixture on the bottom of the prepared pan and 1 in (2 ½ cm) up the sides. Bake in preheated oven to 350ºF (180ºC) and cook for 10 minutes. Remove from the oven and cool. Lower oven temperature to 300ºF (150ºC).
Melt chocolate in a double boiler over hot, not boiling water. Set aside to cool slightly.
Place cream cheese, cocoa and salt in the the mixer and beat until soft and fluffy. Add sugar and continue beating until smooth. Add melted chocolate and beat until mixed. Beat in sour cream until blended. Add eggs one at a time and beat just until blended. Poor filling over the crust. Bake in oven for 1 hour or when small cracks appear around the edge and center jiggles when the pan is moved.
Turn off the oven and leave cheesecake inside with the oven door open to cool. Remove from the oven when cheesecake is warm. Refrigerate covered 6 hours or overnight.
Place heavy cream with chocolate in a medium size saucepan over low heat until chocolate melts and is soft. Stir to blend. Remove from heat and cool chocolate. Pour chocolate mixture over cheesecake and spread with a spatula, leaving 1 in (2 cm) free from the edge. Refrigerate 1 hour or until the topping is firm.
This cheesecake can be prepared up to 3 days in advanced and kept refrigerated and covered with foil. Before serving, loosen sides with a knife. Unmold onto a serving platter and garnish with chocolate shavings.
Strawberry or Raspberry Sauce:Rinse and trim strawberries or raspberries. Place in blender and pulse 2 or 3 times. Transfer to a medium size saucepan and add sugar to taste, ½ cup water and the juice of 1 lemon. Mix and bring to a boil over medium heat 8 – 10 minutes or until the mixture has the consistency of a sauce. Cool.