Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.
In a mixing bowl, combine gluten-free flour, salt, and 1 tablespoon sugar. Add cold butter and mix until the mixture resembles coarse crumbs.
Add ice water, 1 tablespoon at a time, until the dough comes together. Form into a disk, wrap in plastic, and refrigerate for 30 minutes.
Roll out the dough on a floured surface into a 12-inch circle. Transfer to the prepared baking sheet.
In a bowl, toss apple slices with 2 tablespoon sugar and cinnamon. Arrange apples on the dough, leaving a 2-inch border.
Fold the edges of the dough over the apples. Bake for 35-40 minutes, until the crust is golden and the apples are tender.
Let cool slightly before serving. Enjoy!