Preheat oven to 350. Use a food processor to mix the vanilla wafers, butter and sugar until crumbly.
Press into the bottom of a springform pan, then bake for 5 minutes.
Reduce the oven heat to 325, and let the crust cool while you make the cheesecake filling.
Beat the cream cheese in the mixer until it is nice and smooth with no lumps remaining.
Add sugar and salt and mix until smooth.
Add the eggs one at a time, beating the mixture smooth after each. Make sure you scrape the sides and bottom of the bowl after each egg.
Mix in the lemon juice, vanilla, sour cream and heavy cream and stir until smooth.
Pour the batter on top of the crust in the pan and bake at 325 for 60 minutes.
The middle should still be a little jiggly, but the sides should be set. Crack open the oven door a little bit and turn the oven off and let the cheesecake cool in the oven for an hour.
Then take the cheesecake out, and let it sit at room temperature for 45 minutes to continue cooling. Then refrigerate.
To make the topping combine the blueberries with the 1/4 c. of water and bring to a boil in a small saucepan. Once it is boiling mix the cornstarch with the 1 T of water and add it to the blueberries to thicken them up. Let the berries cool for 10 minutes before putting on top of the cake.