In a large mixing bowl, combine cold, leftover mashed potatoes with shredded cheddar cheese, cooked bacon, chopped green onions, garlic powder, salt, and black pepper. Stir in a beaten egg to bind the mixture together.

Scoop out the potato mixture and gently roll it into balls about 1 inch in diameter. Chill in the refrigerator for 15-20 minutes if too soft.

Set up a dredging station: one bowl with flour, another with a beaten egg, and the last with breadcrumbs. Roll each potato ball in flour, then dip in egg, then coat with breadcrumbs.

Heat oil in a deep frying pan to 350°F (175°C). Fry the potato bites in batches for 2-3 minutes until golden brown.

Transfer fried bites onto a paper towel-lined plate to drain excess oil. Serve hot with your choice of dipping sauces.