Preheat the oven to 400°F and line a large baking sheet with parchment paper.
Lightly flour your work surface, then roll out the pie dough into a round 14-inch-wide circle, no less than 1/8 inch thick. **(If you are using store-bought pie dough, it typically comes with 2 pre-shaped dough sheets. Open both and then knead them together into one disk before rolling out.)
Carefully transfer the rolled dough onto the lined baking sheet.
Wash, peel and remove the seeds from the apples. Slice them into even slices, about 1/4-inch-thick slices.
Add the sliced apples, sugar, cinnamon, cornstarch, and lemon juice to a bowl and mix until the apples are fully coated.
Arrange the apple slices in the center or the pie dough, leaving about a 1 1/2-inch border of dough around the edges. (Feel free to arrange the fruit in a decorative pattern or simply pile it naturally.)
Fold the edges of the dough over the fruit, pleating as needed to encase the filling. The center should remain open, so the fruit is visible.
Brush the folded edges lightly with egg wash and sprinkle with coarse sugar for extra crunch and sweetness.
Bake at 400°F for 45-50 minutes, until the crust is golden brown and the apples are tender.
Remove from the oven and let the galette cool on the baking sheet for about 10 minutes before slicing.
Drizzle with caramel sauce and serve warm with a scoop of vanilla ice cream or plain.