- Cook the potatoes, in their skins, in salted water for 15 minutes, or until tender. Drain and leave them to cool.
- Meanwhile, heat half the butter in a large frying pan and cook the onions gently until they are evenly golden. Remove the pan from the heat and set aside.
- Skin the cooled potatoes and cut them into slices about 5 mm thick. Add the remaining butter to the pan with the onions and, when it is melted, turn the heat up a little and add the potato slices. Cook, stirring to ensure that the potato slices do not stick together, for a further 10 minutes, or until the potatoes are well coloured. Season to taste, stir in the chopped parsley and serve the potatoes at once with steak or other meat.
*Herbed Potatoes: To make herbed potatoes, prepare as for Potatoes Lyonnaise, but sprinkle the potato and onion with 1/2 teaspoon dried oregano, 1/4 teaspoon dried rosemary and 1 clove garlic, peeled and chopped, along with the salt and pepper.
*Galette Lyonnaise: Prepare as for Potatoes Lyonnaise, but stir the potato with the onion for 5 minutes only, then transfer the mixture to a gratin dish and carefully smooth the top with the back of a spoon. Brush with a little more butter and cook under the grill until it is golden brown.