1 1/4 cups all-purpose flour
2 tablespoons sugar, plus more for sprinkling
1/2 teaspoon salt
1/2 cup (1 stick) unsalted butter, cold
3 tablespoons ice water
6 tablespoons strawberry jam
1 egg, beaten
Put the flour, sugar, salt and butter in a food processor and pulse until it resembles cornmeal. With the machine running, add the ice water all at once and process until the dough gathers into a ball.
Turn the dough onto a sheet of plastic wrap. Press into a disk and refrigerate for 30 minutes.
When ready to assemble, preheat oven to 425 degrees F and line a baking sheet with parchment paper or lightly buttered foil (not wax paper). Divide the dough into 6 balls. On a lightly floured surface, roll each ball into a circle 5 inches in diameter.
Put a heaping tablespoon of jam in the center of each circle and fold the dough over into a half-moon shape. Use a fork to press all around the outside edges to seal, and then use the fork to poke a few vent holes in the top crust.
Brush the top with beaten egg and sprinkle with sugar. Bake 10 to 12 minutes, until golden brown. Cool before eating.