Prepare the Crust
Preheat oven to 325°F (165°C).
Mix graham cracker crumbs, sugar, and melted butter until combined.
Press firmly into the bottom of a 9-inch springform pan.
Bake for 10 minutes, then let cool.
Make the Cheesecake Filling
In a large bowl, beat cream cheese and sugar until smooth.
Add eggs, one at a time, mixing after each.
Mix in sour cream, vanilla, and lemon juice until smooth.
Bake the Cheesecake
Pour the batter over the cooled crust.
Bake for 50-55 minutes, or until the center is slightly jiggly but set.
Turn off the oven, crack the door, and let the cheesecake cool for 1 hour.
Refrigerate for at least 4 hours (preferably overnight).
Make the Berry Topping
In a saucepan, heat blackberries, raspberries, sugar, and lemon juice over medium heat.
In a small bowl, mix cornstarch and water; stir into the berry mixture.
Cook until thickened (5-7 minutes), then let cool.
Assemble And Serve
Pour the cooled berry topping over the cheesecake.
Garnish with fresh berries, slice, and enjoy!