Roughly chop and bash all the parsley stems. Mince one-third of the parsley sprigs and reserve for the garnish. Roughly chop the remaining sprigs.
Melt the butter with the oil in a saucepan and add the chopped onion and potato. Stir and cook for a few minutes before adding the garlic and roughly chopped parsley sprigs and stems. Stir again to make sure the parsley is well coated with th