Cut blemishes off apples and cut into chunks to fill 3.5 quart crockpot. Add sugar, cider and lemon juice. Cover and cook on Low for 8 hours. Stir. Add cinnamon and cook another 10 hours. Stir occasionally until brown. Run through food mill or any strainer to strain out seeds and skins. To thicken, if not thick enough, return to slow cooker and cook on High uncovered until desired consistency.