While the oven is heating, thinly slice the apples only cutting halfway down. Place them in the baking dish and brush with melted butter. Cover and bake for 20 minutes.
While the apples are baking, in a mixing bowl combine the brown sugar, remaining butter, salt, cinnamon, allspice, and nutmeg. Once the 20 minutes are up brush the apples with the brown sugar mixture and bake uncovered for another 25 minutes. Baste the apples in the sauce at least twice while baking.
Once the apples are cooked drizzle with the bourbon salted caramel sauce and serve. Tastes really good with a scoop of ice cream.