Bring a large pot of salted water to a boil and cook large pasta shells according to package directions.
Drain and cool the pasta shells.
Combine ricotta cheese, large curd cottage cheese, Mozzerella cheese, parmesan cheese and egg together in a large bowl.
Add cooked ground beef and drained, chopped frozen spinach. Stir to combine.
Fill pastry bag, with out a tip, and pipe the filling into each shell.
In a 9x13, spread one jar of your favorite pasta sauce.
Place the filled shells on the sauce.
Sprinkle with mozzarella cheese, cover with foil.
Bake at 425 for 35-45 minutes, removing the foil the last 10 minutes to brown the cheese.