In a food processor, combine flour, salt, and sugar by pulsing them together. Incorporate cold butter and pulse the mixture until it looks like coarse crumbs.
Slowly incorporate ice water, using a pulsing motion until the dough forms a cohesive mass.
Form dough into a disk, wrap it in plastic, and refrigerate for 1 hour.
Preheat oven to 375°F.
Combine blueberries with sugar, cornstarch, lemon juice, zest, and cinnamon.
Shape the dough into a 14-inch round on parchment paper that has been dusted with flour.
Spoon filling into the center, leaving a 2-inch border.
Fold edges over-filling, pleating as you go.
Brush the crust with egg wash and sprinkle it with coarse sugar and almonds.
Cook for 45-50 minutes until the crust turns a golden color and the filling starts to bubble.