Pie crust: Add the all purpose flour, sugar and salt together in a food processor. Add the cubed butter in. Now begin to pulse once or twice. Add ice cold water and pulse until a dough forms. Then knead the dough on a lightly floured work surface until smooth. Shape dough into a ball and flatten it into a thick disk. 

Prepare the filling: Mix the apple slices, brown sugar, flour, lemon juice, cinnamon and nutmeg together in a large bowl. 

Preheat oven to 375°F. Line a large baking sheet with parchment paper or a silicone baking mat. Set aside. On a lightly floured work surface, roll dough in to a 12-inch circle. Transfer the dough to the prepared baking sheet. Arrange the apples (not the juices) in to the center of the dough, leaving a 2-3 inch border all around. Gently fold the edges of the dough over the apples, overlapping the dough as necessary. Press gently to seal the edges. Brush the crust edges with egg wash. Bake until the filling is bubbly and the crust is golden brown, about 45-55 minutes. Allow the galette to cool on the baking sheet for 5 minutes before slicing and serving. Drizzle (3) three tablespoons of salted caramel sauce over the galette. Serve with 1-2 scoops of vanilla ice cream.