Wash potatoes and prick with a fork. Bake at 400 degrees for 1 hour or until done. Cool. Dice potatoes and set aside. Melt butter in heavy saucepan. Stir in flour and cook 1 minute, stirring constantly. Gradually add milk, stirring constantly until thickened. Stir in salt and pepper. Add diced potatoes and green onions. Serve with bacon and sour cream. Yield: 10 cups.