12ozjumbo pasta shells, cooked according to package directions
Brown the beef with the onion and garlic in a skillet.
Cook the spinach in a pot with 1 cup water until soft and wilted, about 3-4 minutes. Drain spinach and squeeze out any excess water. Chop the spinach.
Mix the beef, spinach, ricotta, and Italian cheese together. Fill each cooked shell with the mixture.
Spread a bit of sauce from 1 jar of sauce on the bottom of a 9 x13 inch pan. Place half the stuffed shells in the baking dish. Cover with remaining sauce from the open jar.
Cover the pan with foil and bake at 350°F for 45 minutes.
Place the other half of the shells on a flat sheet and freeze. When frozen, place in a freezer container, label with “Stuffed Shells: Thaw, place in pan and cover with foil, and bake at 350°F for 45 minutes”, and return to freezer. Save unopened jar of sauce in the pantry for use with frozen shells.