Preheat the oven to 350°F (180°C) and butter the cups of a 12-cup muffin tin.

Roll out the pie crusts and cut 12 circles using a 3 1/2 " round cutter. Line the muffin cups with them and place in the refrigerator to firm while you make the filling and topping.

Whisk sugar, cornstarch, lemon juice and water in a saucepan over medium heat. Allow mixture to simmer for 2 to 3 minutes to thicken, whisking constantly.

Remove pan from heat and stir in blueberries, vanilla extract, lemon zest and a pinch of salt. Set aside until needed. Note: You can make the filling in up to 2 days in advance.

In a bowl combine brown sugar, sugar, flour, cinnamon and salt, and then cut in butter until mixture resembles large crumbs. Set aside.

Divide the filling evenly into the crust-lined muffin tins. Don't be afraid to fill those puppies up because the fruit cooks down.

Generously top with the cinnamon crumb topping. Again be heavy handed here.

Bake for 40-45 minutes, until filling bubbles and the topping has browned.

Serve warm with vanilla ice cream. Store any leftovers at room temperature for up to 3 days.