A recipe for mashed potato cakes is Crispy Mashed Potato Cakes from the Food Network, which calls for Idaho potatoes, cream cheese, sour cream, eggs, butter and scallions. Another good recipe uses already mashed potatoes, along with flour, butter, salt and pepper.
In order to make crispy mashed potato cakes, peel and cut 2 large Idaho potatoes, then boil them over medium heat until they soften. Combine the potatoes, 4 ounces of softened cream cheese and 2 tablespoons of sour cream in a bowl, and mash. Stir in 2 finely chopped scallions, 2 teaspoons of lemon zest, 1 egg, and salt and pepper to taste. Form the mashed potatoes into patties, and fry them in 1 tablespoon of olive oil and 1 tablespoon of butter in a skillet at medium heat. Cook for eight minutes on each side.
For another recipe, use 2 cups ready-made mashed potatoes or make mashed potatoes from softened potatoes, 1/2 cup of hot milk and 4 tablespoons of unsalted butter. Chill the mashed potatoes before forming them into patties. On a plate, prepare a mixture for the breading from 1/2 cup of all-purpose flour, 1 1/2 teaspoons of kosher salt and 1/4 teaspoons of ground black pepper. Dredge the potato patties in the flour, and fry them in a skillet with 2 tablespoons of unsalted butter and 2 tablespoons of vegetable oil at medium-high heat for 15 minutes on each side.