Preheat oven to 425 degrees F (220 degrees C).
In a large bowl, combine Mashed Potatoes (24 ounce), Shredded Parmesan Cheese (1/4 cup), Shredded Cheddar Cheese (1/4 cup), Egg (1), Coarse Salt (1/4 teaspoon), All-Purpose Flour (2 tablespoon) and Scallion (1/4 cup). Form into tots about 1-inch across.
Roll each tot in Panko Breadcrumbs (1 1/4 cup). Place the tots individually onto shallow baking pans coated with Butter (1/4 cup). The number of pans needed will depend on the size of the pans and the size of the potato tots.
Bake in the preheated oven until brown on the bottom side. Then, use tongs to turn the tots over. Continue to bake until the other side is browned.
Remove from oven and transfer browned tots to a nice serving dish. Serve immediately and enjoy!