The inspiration for this warm salad was southwestern France’s classic cassoulet: a slow-simmered white bean stew featuring duck confit. Our lighter, faster twist marries the slightly bitter bite of watercress with the richness of duck meat and the sweetness of the dressing. It makes a great side for this meal, but could also take centre stage as a main. You can cook the veggies an hour or two ahead of time, but the salad is best thrown together just before serving.