MJaz is right. It isn't gourmet faire, but it is a very simple casserole that my mom has made since the early sixties. Only differences are the addition of some chopped onion when browning the hamburger and we never put ketchup on it. In order to avoid dirtying additional dishes, use a cast iron skillet. Pour the condensed tomato soup into the skillet after browning the meat, then mix in the green beans. Spread leftover mashed potatoes on top and sprinkle some cheese on top of that. Bake at 350 for 30 minutes.
This may not really be 5 stars, but I think that the other review was completely unfair. This is a standard old-time comfort food recipe, and certainly didn't deserve one star. I can't imagine anyone having to throw this simple meal out, unless they have no clue what the ingredients taste like to begin with. It pretty much tastes exactly like you would expect it to.
Now what I expected. Tomato sauce would be much better than using tomato sauce. I had to throw the whole thing away.