Sure if you have instant mashed potatoes, milk and butter.
make up the mashed potatoes, put them in a lightly greased casserole dish. Hollow out a depression in the middle, pour in the soup. add bread crumbs or chunks of bread. Bake until browned on top. Shepherd's pie where I come from, but not across the pond I guess.
Yep what GeorgiaRosa said ,any sort of veggie , and if you happen to have some chicken thats a bonus ,but celery ,canned veggies what ever you have on hand ,OR you could make dumplings on top of the soup that is yummy too