Steam or boil the potatoes for 15–20 minutes until cooked all the way through but not falling apart. Drain the potatoes, then peel them and cut into 1 cm (½ in) thick slices. The potatoes should not crumble, but don’t worry if some do; set to one side.
Heat the oil and sauté the onions for 5 minutes until golden. Remove from the pan with a slotted spoon and set