Creamy mashed potato pie baked with butter, onions, and cheese until golden and comforting.
2 pounds potatoes, peeled and cubed
4 tablespoons butter
1/2 cup warm milk or cream
1 onion, finely chopped
1 teaspoon salt
1/2 teaspoon black pepper
1 cup shredded sharp cheddar cheese
1 egg, lightly beaten (optional)
Extra cheese or butter for topping
Drain potatoes thoroughly for best texture. Warm milk before adding. Broil briefly for a more golden top if desired.