In a large bowl, combine the mashed potatoes, minced red onion, diced chives, minced garlic, cayenne pepper, and shredded cheddar cheese. Stir well to combine all the ingredients evenly.

Beat the eggs in a shallow bowl.

Place the panko bread crumbs in another bowl.

Using a cookie scoop or your hands, form the mashed potato mixture into 1 ½ inch balls. Roll each ball in your palms to ensure they are evenly shaped.

Dredge each potato ball in the beaten egg, ensuring it is fully coated.

Roll the egg-coated ball in the panko bread crumbs, ensuring it is evenly coated.

Place the coated balls on a plate and repeat until all the mashed potato mixture is used.

Heat oil in a deep fryer or large pot to 360°F (180°C). Test the oil by placing the end of a wooden spoon in the oil; if it bubbles around the spoon, the oil is ready.

Carefully place a few potato balls in the hot oil and fry until golden brown on all sides. This will happen quickly, so keep a close eye on them.

Avoid overcrowding the oil with too many potato balls at once.

Using a slotted spoon, carefully remove the fried potato balls from the oil and place them on a paper towel to drain any excess oil.

Season with salt and pepper immediately if desired.

Serve hot with your favorite dip.