My husband grew up outside Columbus, Oh and loves White castle Hamburgers, since Toledo doesn't have a franchise here I went online to find a recipe. I found a casserole recipe which I tried, and after after tinkering with it decided this was just about right. My son and his family gave this a thumbs up and so did my husband. I like to serve it with fries and chili for them and onion rings and wedding italian soup for me. My daughter-in-law and grandsons aren't big on mustard so I put ketchup on 1/2 of casserole for them. I like cheddar cheese but to be accurate you should use american.