Preheat the oven to 400 degrees F. Place the potatoes in a pot of salted water and bring to a boil. Cook for 2 minutes. Remove the pan from the heat and drain. Heat the olive oil in a large ovenproof skillet over medium heat. Add the onions and season with salt and pepper. Cook, stirring, until the onions are caramelized, 8 to 10 minutes. Transfer the onions to a bowl. Place the pan back on the stove and melt the stick of butter. When the butter has melted, cover the bottom of the pan with 1/3 of the potatoes. Cover the first layer of potatoes with 1/2 of the onions. Cover the onions with 1/3 of the potatoes. Repeat the layering until all of the potatoes and onions are used. Place the pan in the oven and cook for 10 to 12 minutes or until the potatoes are golden brown. Remove the pan from the oven. Using a spatula, gently lift the potatoes out of the pan. Slice the lyonnaise into 12 slices. Garnish with parsley.
Yield: 12 servings