Warm up with this hearty Leftover Mashed Potato Soup recipe. Made with potatoes, onion, margarine and cream of mushroom soup. Easy step-by-step instruct…
This Leftover Mashed Potato Soup relies on simple, everyday ingredients such as mashed potatoes, medium onion, diced, margarine or butter and cream of mushroom soup. It comes together quickly and makes 4 servings, at about 273 kcal each. The step-by-step instructions below are written to be easy to follow, even on a busy day.
It works as a light main on its own or as a starter alongside crusty bread, and it's just as good for a cozy night in as it is for feeding a crowd. Leftovers keep well, so it's a smart choice for meal prep too.
Updated Jun 30, 2026