MaryAnn - Tuna casserole = tinned tuna in white or cheese sauce, served with flat noodles or other pasta and cheese on top. So like a pasta bake. One of the staples of my childhood - mum was Canadian so lots of US-type food, including loads of things made with Campbells condensed soup as a base. Come to think of it, I think you can make tuna casserole with the mushroom soup. And watch your salt levels soar.
Mum's show off recipes - late 70s / early 80s were blanquette de veau (sp??), boeuf bourginon, and chocolate mousse. And then when nursery food came into fashion in late 80s as a backlash against nouvelle cuisine she learned to make spotted dick! It was very yummy though, with posh custard.