1 c. chocolate cookie crumbs, made from chocolate wafers
1/4 tsp. cinnamon
1/2 c. unsalted butter, melted and cooled slightly
1 c. sugar
4 lg. eggs
3 (8 oz.) pkg. cream cheese, softened
16 (1 oz.) squares semi-sweet chocolate
1 tsp. vanilla extract
2 tbsp. unsweetened cocoa
3 c. sour cream, room temperature

Two days before serving, prepare the crust. Combine the chocolate crumbs with the cinnamon and 1/4 cup melted butter. Press the mixture into the bottom of a 10 inch spring form pan and chill for 1 hour.

Preheat oven to 425 degrees. In large bowl, with electric mixer at medium speed, beat together the sugar and eggs until light and fluffy. Add cream cheese gradually, beating well after each addition.

Over double boiler, melt the chocolate and let it cool; add cooled chocolate to the egg mixture.

With electric beater at low speed, add the vanilla, cocoa, remaining butter and sour cream. Mix well. Pour the batter into the chilled crust. Place the filled spring form pan on a baking sheet and bake at 425 degrees for about 55 minutes. Allow the cake to cool slightly on a wire rack. Then cover the top with 2 pieces of paper towel and seal with aluminum foil (to prevent top from hardening). Refrigerate the cake in its pan overnight. Just before serving, remove the sides of the pan.