Preheat your oven to 325°F (163°C).
Combine cookie crumbs and melted butter in a bowl, then press firmly into the bottom of a greased 9-inch springform pan.
Bake the crust for 10 minutes, then set aside to cool.
In a large bowl, beat the softened cream cheese and sugar until smooth and creamy.
Add eggs one at a time, mixing on low speed until combined.
Stir in the sour cream and vanilla extract.
Pour half the batter over the prepared crust.
Fold the melted bittersweet chocolate into the remaining batter, then pour it over the plain layer.
Drizzle the melted white chocolate in a spiral pattern over the top.
Using a toothpick, drag lines from the center of the cake toward the outer edges to create a web effect.
Bake for 60 minutes until the edges are set and the center has a slight wobble.
Let it cool at room temperature before transferring to the fridge for at least 4 hours.