Wash apples and orange. Chop apples into quarters (you can leave the stems/seeds etc.) Add them to the slow cooker along with the whole orange.
Add water, cinnamon sticks, nutmeg, clove and allspice. Cook on LOW for 6-8 hours or HIGH for for 3-4 hours. (If you notice the orange spit open at any point during cooking, remove it from the pot so it doesn't make the cider bitter. This has never happened to me, but it can happen.)
One hour before the mixture is done cooking, mash the apples with a potato masher. Replace lid and continue cooking 1 more hour.
Use a fine mesh strainer to strain the contents into a large heat-proof pitcher.
Stir in brown sugar and caramel sauce and stir to dissolve. Serve warm with fresh whipped cream and caramel sauce drizzled on top.
Refrigerate leftovers for 5-6 days. Rewarm to serve.