In a large mixing bowl, combine cold leftover mashed potatoes with one beaten egg, a cup of all-purpose flour, and finely chopped chives. Season generously with salt and black pepper.

Gently fold in desired add-ins, such as shredded cheese, sautéed onions, or cooked spinach.

Lightly flour your hands, then scoop out portions of the mixture and form patties about ½ inch thick and 2-3 inches in diameter.

Heat vegetable oil in a non-stick skillet over medium heat. Cook for 4-6 minutes on each side until golden brown.

Transfer to a plate lined with paper towels to absorb excess oil and serve hot.