Cover the potatoes with cold water and a dash of salt. Bring the potatoes to a boil, and boil for 30-45 minutes until a fork slides through one of the potatoes easily. Drain the potatoes and return them to the hot pot.

To the potatoes, add the butter, sour cream, half the parsley, and white parts of the scallions. Using a potato masher or a wooden spoon, mash the potatoes to combine with the other ingredients. Taste, and add salt and pepper to your preference.

Spread the potatoes in a baking dish and brush with the egg wash. When nearly ready to eat, bake at 425F for 20 minutes until the top is brown and the potatoes are hot all the way through.

Garnish with the rest of the parsley and scallion greens before serving.

Enjoy!