01 - Mix cold mashed potatoes, shredded cheddar cheese, finely chopped green onions, garlic powder, black pepper, salt, and one egg in a large mixing bowl until fully incorporated.
02 - Scoop generous tablespoons of the mixture and form into balls approximately 1 1/4 inches in diameter. Arrange formed balls on a tray.
03 - Set up three separate bowls: one containing flour, one with beaten eggs, and one with breadcrumbs.
04 - Roll each potato ball in flour, then immerse in the beaten eggs, and finally coat with breadcrumbs to ensure an even crust.
05 - Transfer breaded balls to a tray and refrigerate for at least 20 minutes to promote structural integrity during frying.
06 - Pour vegetable oil into a deep fryer or heavy-bottomed pot and heat to 350°F (175°F).
07 - Working in batches, carefully lower the chilled balls into the hot oil and fry, turning as needed, until golden brown and crisp, approximately 2 to 3 minutes per batch.
08 - Lift fried balls from the oil using a slotted spoon and drain on paper towels. Serve immediately while hot.