In a mixing bowl, combine flour, sugar, and salt. Cut in the cold butter until mixture resembles coarse crumbs. Add ice water gradually until dough forms. Shape into a disk, wrap in plastic, and chill for at least 30 minutes.

1. Preheat oven to 375°F (190°C) and line a baking sheet with parchment paper.
2. In a large bowl, toss sliced apples with lemon juice, brown sugar, cinnamon, nutmeg (if using), and cornstarch. Let sit for 5–10 minutes.
3. On a floured surface, roll out chilled dough into a 12-inch rough circle. Transfer to the baking sheet.
4. Arrange the apple mixture in the center of the dough, leaving a 2-inch border around the edges.
5. Fold the edges over the apples, pleating as needed, leaving the center exposed.
6. Brush the crust with beaten egg and sprinkle with coarse sugar if using.
7. Bake for 40–45 minutes, or until the crust is golden and apples are tender.
8. Cool for 10 minutes, then drizzle with caramel sauce before serving.