For Filling:

3 (8 oz.) pkgs. cream cheese, softened
1 c. sugar
1/4 c. flour
2 tsp. vanilla
6 eggs
1 c. sour cream

In a large bowl, mix cream cheese and sugar. Beat until light and fluffy. Add flour and vanilla to mixture and blend well. At low speed, add one egg at a time, beating just until blended. Add sour cream to mixture and blend well. Place 1 3/4 cup of mixture in medium bowl and stir in melted chocolate remaining from crust. Pour 1/2 of plain filling over crust. Top with spoonfuls of 1/2 of the chocolate filling. Cover with the remaining plain filling. Top with spoonfuls of remaining chocolate filling. Using a table knife, swirl chocolate filling through plain filling.

Bake at 325°F for 1 to 1 1/4 hours. Refrigerate 8 hours before serving.

For Crust:

1/4 c. butter
1 c. semi-sweet chocolate chips, melted

Preheat oven to 400°F. In a bowl, mix flour, sugar, and salt. Cut in butter until the mixture resembles coarse crumbs. Stir in 2 tablespoons of melted chocolate. Press mixture into the bottom of a 9-inch spring form pan.