Preheat oven to 350 degrees F (175 degrees C).

Cover the bottom of a 9x13-inch baking dish with pastry for 1 1/2 pie shells, cutting the pastry to fit and filling gaps as necessary.

Stir apples, sugar, flour, and cinnamon together in a large bowl to coat the apple slices. Layer apple mixture over pie crust. Arrange caramels and butter slices on top of apple mixture.

Cut remaining pie pastry into 1- to 2-inch pieces; arrange atop the caramels and butter.

Bake in preheated oven until just beginning to brown, about 1 hour.

Cool in baking dish on a wire rack for 30 minutes, cut into bars.

Beat milk and confectioner's sugar together in a small bowl; drizzle over bars.