01 - In a large mixing bowl, combine cold mashed potatoes, shredded cheddar cheese, finely chopped green onions, garlic powder, black pepper, salt, and one egg. Mix until fully incorporated.
02 - Scoop heaping tablespoon portions and roll each into a ball approximately 1 1/4 inches in diameter. Arrange formed balls on a tray.
03 - Prepare three separate bowls: one with all-purpose flour, one with beaten eggs, and one with breadcrumbs.
04 - Roll each ball in flour, then dip in the beaten eggs, and finally coat thoroughly with breadcrumbs.
05 - Arrange coated balls on a tray and refrigerate for a minimum of 20 minutes to ensure they maintain structure.
06 - In a deep fryer or heavy-bottomed pot, bring vegetable oil to 350°F (175°C).
07 - Fry balls in batches, turning for even browning, until golden and crisp, approximately 2–3 minutes per batch.
08 - Remove fried balls with a slotted spoon and transfer to paper towels to drain excess oil. Serve hot.