Preheat the oven to 400°F (200°C) and line a baking sheet with parchment paper if desired.
In a mixing bowl, combine the mashed potatoes, shredded cheddar cheese, and grated Parmesan cheese. Mix well until the cheeses are evenly distributed throughout the potatoes.
Add the eggs, flour, garlic powder, onion powder, salt, and black pepper to the potato mixture. Stir until everything is combined and the mixture is slightly sticky.
Using a spoon or small ice cream scoop, form small balls or patties from the potato mixture and place them on the prepared baking sheet, leaving some space between each puff.
Lightly spray the tops of the puffs with cooking spray or brush with olive oil for extra crispiness.
Bake in the preheated oven for about 20-30 minutes, or until the puffs are golden brown and crispy on the outside.
Once finished, remove from the oven and let cool for a few minutes before serving.