Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
In a mixing bowl, combine flour, sugar, and salt. Add the cold butter and mix until the mixture resembles coarse crumbs.
Add ice water, one tablespoon at a time, until the dough comes together. Form into a disk, wrap in plastic, and refrigerate for 30 minutes.
In another bowl, mix blueberries, lemon juice, cornstarch, and sugar. Set aside.
Roll out the dough on a floured surface and cut into 4 circles. Place a spoonful of blueberry mixture in the center of each circle.
Fold the edges of the dough over the blueberries, leaving the center exposed. Sprinkle with sugar.
Bake for 20-25 minutes or until the crust is golden brown. Let cool before serving.