Preheat oven to 375°F (190°C).
Roll out one pie crust and place it in a 9-inch pie dish.
In a large bowl, mix apples with flour, cinnamon, nutmeg, salt, vanilla, and sugar.
Pour half of the apple mixture into the crust, drizzle with half of the caramel sauce.
Add the remaining apples and drizzle with the rest of the caramel.
Roll out the second crust and place it over the filling, sealing and crimping the edges. Cut slits for steam vents.
Brush the top crust with egg wash and sprinkle lightly with coarse sea salt.
Bake for 50–60 minutes, until crust is golden brown and filling is bubbling.
Cool for at least 2 hours before slicing and serving.