I have stumbled upon another great use for leftover mashed potatoes- and ham.
I put about 3 good sized slices of really good glazed ham in the food processor and blitzed it into little pieces. Then I dumped it in a bowl with about a cup of leftover mashed potatoes and some smoked Gouda I cut into little cubes. I formed the mixture into patties and put them in the ice box while I put together the breading and heated the oil.
For the breading I mixed panko bread crumbs with some black pepper, dried oregano, garlic and onion powder and some powdered Vermont cheddar. I dipped the patties in a beaten egg, then coated them in the bread crumb mixture. They pan fried in olive oil until they were golden brown and crispy.
They turned out really well. You could do this with any protein and cheese combination.