01 -
In a large bowl, whisk together flour, sugar, and salt. Add the cold butter and cut it in using a pastry cutter or fingers until the mixture resembles coarse crumbs. Gradually add ice water, mixing until the dough just comes together. Shape into a disk, wrap in plastic, and refrigerate for 30 minutes (or up to 2 days).
02 -
Preheat the oven to 400°F (200°C). Line a baking sheet with parchment paper.
03 -
In a medium bowl, gently toss blueberries with sugar, cornstarch, lemon zest, lemon juice, vanilla, and salt. Set aside.
04 -
On a lightly floured surface, roll out the chilled dough into a 12-inch (30 cm) circle. Transfer to the prepared baking sheet.
05 -
Pile the blueberry mixture into the center of the pastry, leaving a 2-inch (5 cm) border. Fold the dough edges up and over the filling, pleating as needed.
06 -
Brush the pastry edges with beaten egg and sprinkle with coarse sugar if desired.
07 -
Bake for 35–40 minutes, until the crust is golden and the filling is bubbling.
08 -
Cool for at least 15 minutes before slicing. Serve warm or at room temperature.