Preheat oven to 425°F

• Allow puff pastry to defrost for 30 minutes, then place on a lightly floured surface and use a rolling pin to flatten.
• Transfer puff pastry sheet to a parchment paper-lined pan and use a fork to prick a series of holes across the pastry to allow steam to escape. Spread jam over the pastry sheet, leaving a 1-inch thick border around the edges. Thinly slice brie and lay in rows across the tart.
• Use a mandoline or a sharp knife to thinly slice apples. Remove core and cut slices in half. Place in a bowl and coat with lemon juice and sprinkle with pumpkin pie spice. Arrange apple slices in 9 different stacks across the sheet, laying them in a different direction each time.
• Whisk egg in a small bowl and brush over the edges of the tart, then use a pastry brush to brush salted caramel sauce onto the apples.
• Place apple puff tart in the oven, and bake for 30 minutes or until edges are golden brown and tart is fully cooked, rotating tray halfway through. Cool for 5 minutes before slicing. Serve plain, sprinkled with powdered sugar, or topped with a scoop of vanilla ice cream.