Put diced bacon into cold water and bring to a boil to blanch the bacon. Drain. Put into a 9-inch skillet with the butter and onions. Stir-fry until bacon is rendered and is somewhat crisp. Spoon off fat.
Peel potatoes. Cut into fourths and then across into eighths. Carve each piece into an olive shape. (Boil trimmings in water and then add cream and some but