Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper or lightly grease it.
Mix mashed potatoes, cheddar cheese, Parmesan cheese, flour, egg, garlic powder, onion powder, salt, and pepper in a large bowl.
Fold in chopped chives if using, for fresh flavor and color.
Portion the mixture onto the baking sheet using a tablespoon or cookie scoop, spacing about 1 inch apart.
Spray or brush tops with cooking spray or oil. Bake for 20-25 minutes until golden brown and crispy. Let cool slightly before serving.
Notes
For an extra crispy texture, chill the mixture in the refrigerator for 30 minutes before baking. You can also use leftover mashed potatoes to save time.