First, remove the dough from the refrigerator and let stand for 15 minutes otherwise it'll break when you're trying to roll it.
Preheat the oven to 375°F.
Line a rimmed sheet pan with non-stick foil, parchment, or a silicone mat.
Gently flatten the refrigerated pie crust flat. Then flour your rolling pin lightly and roll the dough out into an 11-inch circle. Brush off the excess flour.
Transfer the dough to the prepared baking sheet, cover with plastic wrap to prevent it from drying out, and refrigerate for 15 minutes, or while to cook the apples.
In a large bowl, stir together the apples, sugar, lemon juice, cinnamon, and salt.
Spoon the apple filling into the center of the dough. You'll need to mound it in the center slightly. Leave a 2-inch border. Top with marshmallows and caramels.
Now, gently fold the edges of the dough over the apples. Pleat it if necessary. (You can brush the pastry with a beaten egg to help it brown better. I rarely do this step.)
Bake the galette on the middle rack in the 375°F oven until the crust is golden and the apples are tender. It may take 40 to 50 minutes depending on your oven.
Transfer the pan to a wire rack and let the galette cool. (There's nothing I love more than a warm apple pie/galette. Just be aware that if you cut it before it has cooled completely, you won't get clean cuts and it may fall apart.)
Cut the galette into 6-8 slices. Top each slice with vanilla ice cream or whipped cream, if desired. Store in an airtight container in the refrigerator for up to 4 days. The crust gets pretty soggy after that.