First, you take your fresh-shucked green beans, preferably homegrown, but canned will do. Then you boil 'em in water until all the nutritional elements have been fully leached away. Throw the result in a casserole dish and add some mystery sauce to kind of glue them together, and sprinkle chopped bacon on top. Cook in the oven for an hour. Voila, an instant classic.
Some people use a ham hock or pig knuckle instead of bacon.
It's gotta have a pig product, though. Anything else is just cheating. Macaroni and cheese made with Velveeta has a special gooey taste that is positively addictive, and leaves a gross kind of film on your teeth afterwards. That's the hallmark of a really good mac and cheese casserole. You'll want to load your plate.