Preheat oven to 325°F (160°C) and prepare a 9-inch springform pan with parchment paper
Mix graham cracker crumbs, 1/4 cup sugar, and 6 tablespoons butter in a bowl
Press mixture firmly into the bottom of the prepared pan
In a large bowl, beat cream cheese, 1 cup sugar, eggs, and vanilla extract until smooth
Stir in sour cream until fully combined
Pour filling into the prepared crust
In a small saucepan, cook blueberries, lemon juice, and cornstarch over medium heat
Stir until thickened (3-4 minutes), then swirl onto the cheesecake
Place pan in a cooling oven and let sit off heat for 1 hour
Let cheesecake cool completely before refrigerating for at least 4 hours