In a bowl, whisk flour, salt, and sugar.
Cut in butter with a pastry cutter or fork until mixture resembles coarse crumbs.
Add ice water, 1 tbsp at a time, mixing until dough just holds together.
Form into a disk, wrap, and chill 30 minutes.
Heat oven to 375°F (190°C). Line a baking sheet with parchment paper.
On a lightly floured surface, roll dough into a 10–12 inch circle.
Transfer to baking sheet.
Spread jam in the center, leaving a 2-inch border.
Fold dough edges up and over filling, pleating as you go.
Brush crust with egg wash, sprinkle with coarse sugar.
Bake 35–40 minutes until golden and bubbling.
Cool 10 minutes before slicing. Serve warm or at room temp.