The night before, peel and half potatoes into four equal parts. Cook in boiling water for 15 minutes, drain and cool potatoes before putting them into a refrigerator storage bag and refrigerate overnight.
Preheat oven to 375°F.
Morning prep: In a 9-inch cast iron skillet, cook bacon that has been diced until almost crisp. Remove to a paper towel, reserving half of the drippings.
Put pare boiled potatoes through a large grater, making hash browns and put in hot skillet. Lightly mix potatoes with the two diced scallions to coat with oil. Over medium heat, cook potatoes, stirring occasionally, until lightly browned. Turn off heat.
In a bowl, mix the eggs, Parmesan, milk, salt and pepper. Set aside.
Press cooked potatoes in skillet down lightly to form a loose crust .
Sprinkle cooked bacon bits evenly over potato crust.
Pour egg mixture over potatoes and bacon, and sprinkle half of the cheddar on top.
Put into preheated oven on middle shelf for 20 minutes.
Put remaining cheddar cheese on top, and bake for an addition 10 minutes.
Remove from oven, let rest on top of stove for 5 minutes. Slice pie style into 6 equal portions, Serve with topping of choice ( salsa, sour cream, ketchup, etc.
Meat substitutions: ham, breakfast sausage, Canadian bacon, Mexican chorizo (casings removed), Spanish chorizo (diced).