Hasselback potatoes

Place potato on wooden spoon and chop through with a knife (spoon prevents the spud being cut into individual slices).
Boil until almost cooked.
Place sliced side down in a heavy pan with lots of butter and olive oil and cook until golden then turn over and carry on cooking until you think they are done.
Serve with a sprinkle of salt crystals.
Nigela says to roast them but this seems to work better for me.