In a large bowl, whisk together flour, sugar, and salt.

Add in cold butter cubes and cut them in with a pastry cutter until there are not overly large pieces.

Add water and mixing with a spatula, then knead gently to form a ball ensuring any pieces that did not stick initially to the ball, do.

Flatten into a disk, wrap tightly in plastic wrap, and chill for at least 1 hour (I like to do 2 hours).

In a medium bowl, mix all blueberry filling ingredients and let sit 10 minutes.

Preheat oven to 375F and prep a rimmed baking sheet with parchment paper.

Roll out chilled dough into a 12" circle and transfer to the baking sheet.

Use a slotted spoon to pile berries into the center of the dough, leaving a 1½–2” border. Fold the edges of the dough over the berries, pleating as needed.

Brush crust with egg wash. If desired sprinkle the crust with coarse sugar and add lemon zest to the filling.

Bake for 45 minutes, until deeply golden brown and bubbling.

Cool slightly, then slice and serve warm.