Preheat your oven to 325°F (160°C).

In a mixing bowl, combine graham cracker crumbs, sugar, and melted butter. Mix until all crumbs are moistened.

Press this mixture firmly into the bottom of the springform pan. Bake for 10 minutes. Remove from oven and let cool.

In a large bowl, beat the softened cream cheese until smooth with an electric mixer.

Gradually add the sugar, continue to beat until creamy.

Add eggs one at a time, mixing well after each addition.

Stir in vanilla extract, melted white chocolate, and sour cream. Mix until smooth.

In a small saucepan, combine the raspberries, sugar, and lemon juice. Cook over medium heat until the raspberries break down, stirring frequently.

Stir in the cornstarch mixture and cook for another 1-2 minutes, until the sauce thickens. Remove from heat and let cool.

Pour half of the cheesecake filling over the cooled crust.

Drizzle some raspberry sauce over the filling and swirl it gently with a knife to create a marbled effect.

Pour the remaining cheesecake filling over this layer, and top with another swirl of raspberry sauce.

Place the cheesecake in the preheated oven and bake for about 60-70 minutes, or until the center is set but still slightly wobbly.

Turn off the oven, crack the oven door, and let the cheesecake cool in the oven for about 1 hour.

Remove the cheesecake from the oven and let it cool to room temperature.

Cover and refrigerate for at least 4 hours, preferably overnight.

Before serving, you can drizzle more raspberry sauce on top and garnish with fresh raspberries if desired.