Brown ground beef and chopped onion in a large skillet. Drain, then stir in 1–1½ tsp Worcestershire sauce, salt, and pepper.
Cook macaroni noodles and drain.
Add meat mixture to noodles and stir well.
Add one large can of undrained tomatoes and mix.
Stir in ¾ lb sharp cheese until combined.
Transfer to a casserole dish (8x8”, 9x9”, or at least 2 quarts).
Sprinkle Parmesan cheese on top.
Bake at 350°F for 50 minutes to 1 hour.
