For the all-butter pastry dough (enough for one tart):
8 tablespoons (1 stick) unsalted butter, very cold
1/2 cup ice water, divided
1 1/4 cups all-purpose flour
1 1/2 teaspoons sugar
1/2 teaspoon sea salt

For the apple filling and glaze
2 pounds of tart, firm apples, any variety. They should be peeled, cored, and cut into quarter-inch slices (save the peels and cores)
2 tablespoons unsalted butter, melted 5 tablespoons granulated sugar, plus 1/2 cup for glaze