CRUST:

9 oz. pkg. Nabisco chocolate wafers
1/2 c. butter, melted
1/3 c. sugar

CAKE FILLING:

12 oz. cream cheese, softened
1 c. sugar
4 eggs
1/3 c. heavy cream
5 tbsp. Kahlua
1 tsp. vanilla

CAKE TOPPING:

8 oz. sour cream
1 tbsp. sugar
1 tsp. vanilla

Put wafers in a blender or food processor (or roll into fine crumbs on wax paper with rolling pin). Blend until fine. Mix chocolate wafer crumbs in bowl with butter and sugar. Press into bottom of greased 9 inch springform pan. Cake filling: In large mixing bowl, cream together cream cheese and 1 cup sugar. Add eggs, one at a time, beating well after each. Add heavy cream, Kahlua and 1 teaspoon vanilla. Blend well. Pour batter into wafer shell and bake at 375 degrees for 45 minutes. Transfer cake to wire rack for 5 minutes while preparing the topping. In a small bowl, combine sour cream, 1 tablespoon sugar and 1 teaspoon vanilla. Blend well. Spread evenly over cake and return cake to oven for 5 minutes. Let cake cool to room temperature and then chill at least 2 hours.