Core, peel and cut the apples into about 1-inch pieces.
Add the apples and sugar (use less sugar if your apples are really sweet) to an 6-quart crockpot. I use anywhere between 2 tablespoons and 1/4 cup of sugar.
Add the cinnamon if desired.
Cover and cook the apples on LOW heat for 6 hours.
For chunky applesauce, gently break up the apples with a potato masher. For smoother applesauce, blend the apples with an immersion blender.
Transfer the applesauce to an air tight container. Refrigerate overnight before eating.