Preheat oven to 400°F. Line a cookie sheet with parchment paper or silicone baking mat.
Stir together brown sugar, cinnamon, and nutmeg. Set aside.
Slice pears 1/16-inch (1mm) thick. Place in a large bowl and toss with lemon juice, then add sugar mixture and toss to coat.
Roll out pie crust on a large piece of parchment paper or a silicone baking mat. Roll dough into a 12-inch circle.
Arrange the pears (without any juices) in the center of the pie crust circle, leaving a 2-inch border. Drizzle with caramel (just over the pears).
Fold up the edges gently and place over the pears, overlapping as necessary. Brush with egg wash.
Bake 28-32 minutes, or until golden. Let cool to room temperature and drizzle with additional caramel before serving.
Store covered in the refrigerator for up to 3 days.