Growing up in the 50’s and 60’s we had leftovers all the time. My Mom was pretty good at putting two disperate items together. We would have hot dogs and scrambled eggs or the left over roast beef with macaroni and cheese. If there were parsnips left over she would fry them in butter(That’s before we knew what saute was.) and serve them with pork chops. Yorkshire pudding and gravy would be a meal.
Sally Schneider has a new book out called "The Improvisational Cook". I have not finished it yet but it opens your eyes to the food you can create with the stuff you have on hand.