I've been getting lazy with dinners lately, but there's always time for my mom's casserole. Literally we only ever called it "casserole." It's just ground beef, onions, canned tomatoes and mac and cheese.
Preheat oven to 350°F.
Cook mac and cheese according to box instructions. Sauté onions and beef until browned. Mix together cooked mac and cheese, beef mixture, and tomatoes and put in a casserole dish. Cover and cook in the oven for 30 to 60 minutes. (Depends on how impatient you are. I like it cooked longer so the top layer of noodles gets crispy!)
I sometimes will add peas too. And sometimes I'll add a slice of American cheese on top then microwave it!