Preheat your oven to 375°F (190°C).
Prepare the pie crust in a 9-inch pie dish.
In a large mixing bowl, combine the sliced apples, granulated sugar, cinnamon, nutmeg, lemon juice, and flour.
Pour the apple mixture into the prepared crust.
Drizzle half of the caramel sauce over the apples.
In another bowl, mix the rolled oats, brown sugar, flour, and melted butter until crumbly.
Spread the crumble topping over the apple filling.
Bake the pie for 45-50 minutes or until the top is golden brown and the apples are bubbling.
Let the pie cool for at least 30 minutes before serving.
Serve with a drizzle of remaining caramel sauce on top, if desired.