In a large bowl, combine the mashed potatoes, parmesan cheese, onion, 1/4 cup flour, egg, garlic powder and parsley. Season with salt and pepper and mix well until smooth. If the mixture is too thin, add more flour, 1 tablespoon at a time, until you can mold it into balls. Do not overdo it, as we are after soft, melt-in-your-mouth pancakes.

Roll the dough into balls and flat them into 1/2-inch-thick pancakes. Add the remaining flour to a plate and dredge each pancake in the flour.

Heat 1/4 cup of oil in a skillet over medium hear and fry the pancakes, in batches, until crispy and golden brown, about 3 minutes per side. Add more oil as needed. Transfer the pancakes to a paper towel-lined plate to soak up any excess grease.

Serve the mashed potato pancakes immediately, topped with sour cream and chopped chives or scallions.