Preheat oven to 400. Boil water in large pot. Grease 13x9 pan well, including sides.
Boil pasta just long enough the noodles are workable but not fully cooked (usually 8-9 minutes). Drain and immediately cool with cold water. I like to boil a few more shells than I'll eventually need because often a couple tear.
Add sauce to bottom of pan.
Stuff each shell with filling. (I use a melon baller for ease, and I use 2 heaping scoops in each shell. Arrange shells tightly in pan, filling side up.
Cover with sauce.
Generously cover with mozzarella and parmesan. Sprinkle chopped parsley over top.
Cover with foil tightly. Bake in oven 30 minutes. Remove foil. Bake 5 minutes. Let cool 20 minutes before serving.
