Prepare springform pan cover outer bottom with 2 layers foil.
Moisten graham cracker crumbs with melted butter and sugar.
Press mixture into bottom and up side of pan to form crust. Refrigerate to set.
In a food processor, combine the cream cheese, eggs, sugar and vanilla extract and pulse until smooth.
Combine this mixture with the heavy cream and sour cream in a large bowl, lightly stir with whisk to just combine.
Preheat the oven to 275°F degrees
Place a roasting pan half filled (about an 1" high) with hot water on the middle rack.
Pour the filling into the springform pan, smooth the surface and place the pan into the water bath.
Bake slowly, 1 – 1 ½ hours Mixture should still jiggle and not be completely set.
Do not allow the cheesecake to brown and puff up.
Crack open the oven door to cool it down slightly. (20- 25 minutes)
Remove the pan from the water bath and remove the aluminum foil.
Place the pan on a rack to cool to room temperature.
Refrigerate the cake when cool and let set at least 6-8 hours before serving.
Topping: In saucepan combine 2 cups of blueberries, sugar, water and juice of one lemon. Stir until sugar dissolves then add cornstarch. Cook over medium heat, bringing to a low boil to thicken. Remove from heat. Gently fold in remaining blueberries. Let cool slightly and pour over chilled cheesecake. Sprinkle with lemon zest prior to serving.