In a medium bowl, combine cold leftover mashed potatoes with sharp cheddar or pepper jack cheese, chives, and garlic powder, seasoning with salt and pepper to taste.

Using a cookie scoop, portion out the mixture into 1-inch balls and roll them gently to create a smooth shape.

Set up a breading station with all-purpose flour, a beaten egg, and panko breadcrumbs. Dredge each ball first in flour, then dip in the egg, and roll in panko.

In a small pot, heat oil to 375°F (190°C) and carefully add the breaded boxties in batches, cooking for 2-3 minutes until golden brown and crispy.

Serve the boxties immediately while still warm and crispy with your choice of dipping sauces.