The combination of cooked and fresh blueberries makes this pie amazing.
Quickest and easiest to make using a frozen pie crust, but would probably be even better using your favourite pie dough recipe from scratch!
Bake pie shell according to directions, and let cool while making the filling.
Add 2 cups blueberries, sugar, lemon zest, lemon juice, and 1 cup water to saucepan and bring to a boil.
Reduce heat, stirring occasionally until the berries burst.
Remove from heat.
Make a slurry of the 2 tablespoons cornstarch and 2 tablespoons water, and stir into sauce pan.
Add remaining 2 cups of blueberries, folding into the thickened mixture.
Combine topping ingredients into a frozen mixing bowl, and whip until stiff peaks form.
Fill baked pie shell with the blueberry filling.
Serve and add a couple good dollops of the topping with each slice.