Preheat oven to 325°F (160°C) and grease a springform pan.
Mix biscuit crumbs with melted butter, press into pan base, and bake 10 minutes then cool.
Cook blueberries, sugar, lemon juice, and cornstarch until thick to create sauce, then cool.
Beat cream cheese and sugar until smooth, then mix in eggs one at a time.
Blend in sour cream and vanilla until creamy.
Pour cheesecake batter over crust and spoon blueberry sauce on top.
Swirl sauce gently with a knife to create patterns.
Bake 55–60 minutes until center is slightly set.
Cool gradually, then refrigerate at least 4 hours or overnight before serving.