Preparation 1. Preheat oven to 500º . Place a heavy cast-iron Dutch oven with lid inside while pre-heating.2. Toss potatoes, onions, and garlic with olive oil. Season well with salt and pepper.3. Season chicken breasts on both sides with salt and pepper.4. When Dutch oven is very hot, place potato mixture in Dutch oven. Place half the rosemary sprigs ontop, then chicken breasts, then remaining rosemary sprigs.5. Close lid and cook for 45 minutes without opening. Gently shake Dutch oven occasionally to movepotatoes around.6. When done, remove chicken and potatoes to a platter. Place Dutch oven with onions and garlic on aburner. Add chicken stock, bring to a boil, and simmer until reduce by ½ to 2/3.7. Remove from heat, stir in butter, and serve with potatoes and chicken. A crispy, simple salad oficeberg lettuce and mild blue cheese goes nicely with this dish.