Step 1 of 5

Parboil until the edges give

Heat the oven to 425°F. Put the potato chunks in a large pan of cold water with the salt, bring to a boil, and cook until a knife slides into the outside easily while the middle still resists. Drain them thoroughly.

— Start them in cold water, not boiling. Dropped into hot water the outsides disintegrate before the middles have begun.