Prepare the Raspberry Sauce: In a small saucepan, mix together raspberries, sugar, and lemon juice. Cook over medium heat for 5–7 minutes until the raspberries break down and release their juices. Combine cornstarch and water, stirring until smooth, then add to the raspberry mixture. Cook until thickened, cool completely.

Make the Chocolate Cookie Crust: Preheat your oven to 325°F (160°C). Combine chocolate cookie crumbs, granulated sugar, and melted butter in a mixing bowl. Press the mixture firmly into the bottom of the springform pan. Bake for 8 minutes, then cool completely.

Create the White Chocolate Truffle Layer: Heat heavy cream in a saucepan until steaming, then pour it over chopped white chocolate. Let sit for 2 minutes, stir until smooth. Spread this mixture over the cooled crust and freeze for 10 minutes.

Prepare the Cheesecake Filling: Beat softened cream cheese and granulated sugar until creamy. Add eggs one at a time, mixing on low speed. Incorporate vanilla extract, sour cream, and heavy cream. Fold in melted white chocolate until fully combined.

Assemble the Cheesecake Layers: Pour half of the cheesecake batter over the truffle layer. Drizzle half of the raspberry sauce and swirl gently. Add remaining cheesecake batter and raspberry sauce for a marbled effect.

Bake the Cheesecake: Create a water bath by placing the springform pan inside a larger dish filled with hot water halfway up the sides. Bake for 60–70 minutes until the edges are set. Let cool in the oven with the door cracked for an hour.