Preheat oven to 400 °F (200 °C). Line a baking sheet with parchment paper or lightly grease.

In a mixing bowl, combine mashed potatoes, cheddar and Parmesan cheeses, beaten egg, chives, garlic powder, onion powder, salt, and pepper.

Add flour a little at a time and mix gently until the mixture holds together enough to form small puffs.

Using a cookie scoop or spoon, shape heaping tablespoon-sized portions and place them on the prepared baking sheet, spacing about 1 inch apart.

If desired, use a fork to press the tops lightly for a crispier finish.

Bake for 18–20 minutes, until edges are golden and the tops are lightly crisp.

Remove from oven and let cool for 2 minutes before serving warm.