Pasta Shells

Jenna made Pasta Shells for January.  Here is her recipe:

1 box large pasta shells
1 1/2 jars spaghetti sauce
2 lb. ground beef, browned
1 small tub ricotta cheese
1-8oz. bag mozzarella cheese

Cook pasta shells according to package directions. Run cold water over
shells so they are cool enough to handle. Brown hamburger and add
spaghetti sauce. Put shells in a sprayed 9X13 casserole dish and fill
each with a spoonful of sauce mixture and a small scoop of ricotta
cheese. Cover with remaining sauce and top with mozzarella cheese. If
baking immediately, bake at 350 for 25-30 minutes. Freezer directions:
Thaw. Bake at 350 for 45 minutes or until heated through.