Wash but do not peel apples. Cut apples into quarters, removing the core, then place apple chunks in a large microwave-safe bowl. Add lemon slices, a sprinkle of ground cinnamon, then pour water right on top.
Microwave on high, then stir. Cook additional minutes on high power. Repeat with remaining apples.
Discard lemon slices, then use a slotted spoon to transfer cooked apples into a foley mill fitted with small-size holes. Process the apples, which should turn into sauce easily. As apple skin accumulates and blocks the holes, remove and throw away. Repeat with remaining apples.
Add sugar to taste — make sure to try the cinnamon applesauce before adding any in case your apples are sweet enough without! Then add a few tablespoons at a time, taste, and reassess. Cover, then cool in a refrigerator until needed.