To make the applesauce: Core and cut the apples in quarters (you don't need to peel them, but you can). In a large stockpot, add apples and about 1 inch of water. Bring to a boil; cover, and reduce heat. Simmer until apples are tender.
When the apples are cool enough to handle, place the food mill over a large bowl. Add two or three ladles of cooked apples to the food mill and turn the handle clockwise to mill the food over the milling disc. Discard the skins and seeds that remain in the food mill. Repeat until all of the cooked apples are milled.
To make the apple butter: Fill a crockpit with the applesauce. Add 2 cups of the sugar to the applesauce and mix well. As mixture cooks, add additional sugar as needed to suit your taste. Cook, uncovered, on low for about 12 hours, or until mixture is thick and dark. Let cool slightly then add cinnamon, 1 teaspoon at a time, and mix well. Add additional cinnamon as needed. (Note: the apple butter will not thicken if it is covered. I leave the cover slightly off by about two inches so that it doesn't splatter.)
To jar the apple butter: Prepare jars, lids, and rings according to manufacturer's instructions but keep the jars hot so that they don't crack when the jars are filled with hot apple butter. Fill jars using the jar funnel. Make sure you leave about ½ of free space at the top of the jar; add lids and rings and tighten. Bring enough water to a boil in the waterbath canner to cover jars by about 1 inch. Use jar lifter and add jars to the boiling water. Cover, and cook for about 10 minutes. Remove jars from the waterbath and cool completely. Make sure jars are sealed by pressing the lids in. If the center of the lid pops in and out, the jars did not seal properly. If this happens, refrigerate apple butter and use immediately.