Crust:
1 cup Graham crumbs
1/2 pecans or walnuts, ground
1/3 cup butter, melted

Filling:
1,5 lb (680 g) cream cheese, at room temperature
3 tbsp sugar
3 eggs, at room temperature
1 tsp vanilla
1 cup sour cream
2 tbsp all purpose flour
100 g white chocolate
50 g dark chocolate
1 tbsp cocoa powder

1. Preheat oven at 350F.
2. Combine the nuts, crumbs and melted butter. Press evenly onto the bottom of one 9" spring form pan or six 4" pans. Bake for 5-8 min. Set aside to cool.
3. Melt both chocolates and set aside.
4. For the filling, beat the cream cheese and sugar with an electric mixer until smooth. Add vanilla and sour cream and beat until blended.
5. Take 1/3 of the mixture to a separate bowl, add dark chocolate and cocoa powder and mix it in. Beat in 1 egg just until incorporated.
6. Add to remaining filling flour and melted white chocolate and beat until blended. Beat in remaining eggs 1 at a time. Do not overmix.
7. Spoon dollops of white chocolate filling on top of the baked crust in pan, repeat with dark chocolate mixture, filling in empty spaces. Using a skewer, swirl the two colors together to create a marbled appearance.
8. Illuminate the pan with tin foil and place into a baking pan with edges, and fill pan with boiling water 1 inch up the sides.
9. Bake in 325F oven for about 35-40 min. Cool cheesecake for 30 minutes, then run a spatula of knife gently around the edge of the cheesecake, to loosen (this will prevent any cracking). Cool cheesecake to room temperature and chill overnight.