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 the mixture is completely uniform.
02 - Using heaping tablespoons, portion out the mixture and roll each piece into a ball approximately 1 1/4 inches in diameter. Arrange the formed balls on a tray.
03 - Arrange three shallow bowls: one with all-purpose flour, one with the beaten eggs, and one with the breadcrumbs.
04 - Coat each potato ball by rolling first in flour, then dipping in beaten eggs, and finally coating thoroughly with breadcrumbs.
05 - Transfer the breaded balls to a tray and refrigerate for at least 20 minutes to ensure they remain firm during frying.
06 - Pour vegetable oil into a deep fryer or heavy-bottomed pot to a suitable depth and heat to 350°F (175°C).
07 - Fry the balls in batches, turning as needed, until golden brown and crispy, approximately 2 to 3 minutes per batch.
08 - Remove the fried balls with a slotted spoon and drain on paper towels. Serve hot with your preferred dip.