These Best Ever Leftover Potatoes, solve the problem of dull leftover mashed potatoes. I don't know about you, but I love leftovers! There are those certain dishes that are always better the next day, leftover spaghetti, for instance. A ham sandwiches after Easter, and almost any casserole. But mashed potatoes seem to decline. This recipes takes those plain, boring potatoes and turns them into a dish that is better than the original!