Place the spinach into a clean dish towel and squeeze out any excess liquid.

Cook shells according to package directions, drain,  and cool shells for a few minutes on a piece of waxed paper or foil.

In a large bowl, mix together the spinach, mozzarella, 1/2 cup of Parmesan, ricotta, and egg with a little salt and pepper.

Using a cookie scoop or spoon, stuff approximately 1 1/2 Tbsp of the cheese mixture into each shell.

In two 9x9 or 11x7 inch baking dishes, spread a couple of spoonfuls of spaghetti sauce into the bottom of each dish.  Add the tomato sauce to the remaining spaghetti sauce in the jar and stir to combine.

Place half of the shells in each of the baking dishes.  Pour half of the remaining sauce over one dish of shells and pour the rest over the other dish.  Sprinkle the remaining Parmesan over the shells.

Cover dishes with foil and bake one and freeze one.  Bake at 350 degrees for 30-45 minutes until hot and bubbly.  To prepare the frozen dish, bake at 350 degrees at 350 degrees for 1 hour and 30-45 minutes.  You should get about 40-45 shells between both pans.  One pan will serve 5.