Thoroughly wash the parsley then remove and discard the stems. Chop the remainder coarsely. Scrape the potatoes and cut into large dice. Peel and finely chop the onion.
Melt the butter in a large saucepan. Add the onion, cover with a lid and fry gently without browning for a few moments until the onion is soft. Add the potatoes and chopped parsley and fry for a further few moments over