Peel potatoes. Grate potatoes and onion fine. Dice bacon and fry until crisp. Pour fat and bacon over potatoes. Add hot milk then add eggs, one at a time and beat after each addition. Add pepper and salt and flour; mix well. Pour into greased heavy skillet or pan. Bake at 400 degrees for 15 minutes. Reduce heat to 375 degrees and bake 45 minutes longer. Cut into squares. Serve hot with sour cream. Bake until it is golden brown and crisp.