Leftover Mashed Potato Patties Recipe. Leftover mashed potatoes about 1 quart1 onion, diced. Flourbutter. Salt and pepper. Combine mashed potatoes, onion, egg and cheese. Shape into large size balls. Mashed potatoes can be made almost completely ahead. Do nearly everything boil, peel and mash stir in milk and salt up to two days ahead. Before serving, reheat. Shepherds Pie with Healthier Mashed Potatoes That Actually Taste Good will fool even the most diehard mashed potato lover Tired of the same old mashed potatoes, I whipped up this new family favorite. We cant get enough of them at our house. Often, Ill prepare this dish ahead and. Roll into flour and flatten into patties. Melt butter in frying pan and brown for about 5 minutes on each side. Salt and pepper to taste. Healthy Asian Noodles. Leftover mashed sweet potatoes are not easy to reheat and serve without turning them too dry or worse, scorching them on the bottom of a pan. Instead of trying, use. A warm, buttery serving of creamy mashed potatoes is an ideal coolweather comfort food. Heres how to make the best potatoes ever.