1. Prepare the Crust:

• Preheat your oven to 350°F (175°C).
• In a medium bowl, combine the graham cracker crumbs, sugar, and melted butter. Mix until well combined.
• Press the mixture into the bottom of a 9-inch springform pan. Bake for about 10 minutes or until lightly golden. Remove from the oven and let cool.

2. Make the Cheesecake Filling:

• In a large mixing bowl, beat the softened cream cheese until smooth.
• Add the granulated sugar and vanilla extract, mixing until well combined.
• Add the eggs one at a time, mixing on low speed until just combined. Avoid overmixing.
• Stir in the melted white chocolate and sour cream until smooth.
• Pour the cheesecake filling over the cooled crust and smooth the top.

3. Bake the Cheesecake:

• Bake the cheesecake in the preheated oven for about 50-60 minutes, or until the center is set but still slightly jiggly.
• Turn off the oven and let the cheesecake cool in the oven with the door slightly ajar for about 1 hour. This helps prevent cracking.
• Remove from the oven and refrigerate for at least 4 hours or overnight.

4. Prepare the Blackberry Mousse:

• In a saucepan over medium heat, combine the blackberries, sugar, and lemon juice. Cook until the blackberries break down and the mixture thickens (about 5-7 minutes). Strain to remove seeds and let cool.
• If using gelatin, dissolve it in 2 tablespoons of warm water and let it sit for a few minutes. Then, stir it into the cooled blackberry mixture.
• In a separate bowl, whip the heavy cream until soft peaks form. Gently fold the blackberry mixture into the whipped cream until fully combined.

5. Assemble the Cheesecake:

• Once the cheesecake is chilled, spread the blackberry mousse evenly over the top.
• Garnish with additional fresh blackberries if desired.

6. Chill and Serve:

• Refrigerate the assembled cheesecake for at least 2 hours before serving to allow the mousse to set.
• Slice and enjoy your delicious White Chocolate Blackberry Mousse Cheesecake!