Preheat oven to 425. Scrub potatoes under cold running water and pat dry with a kitchen towel. In a roasting pan combine the potatoes, olive oil, salt and pepper. Using a large spoon or by shaking the pan from side to side, coat the potatoes evenly with the oil mixture. Roast the potatoes for 20 minutes. Sprinkle evenly with the onion and drizzle evenly with the chicken stock. Continue roasting, shaking the pan every 10-15 minutes to rotate the potatoes, until they are brown and crusty and the onions are caramelized, 1-1.25 hours longer. Taste and adjust the seasoning. Transfer to a serving bowl and garnish with the parsley. Serve immediately. NOTES : Substituted beef for chicken broth when serving with steak. Shallots or mild yellow onions also work well.