Roasting a whole duck at home can be an ordeal. Instead, I use this technique—it’s well worth knowing—of tying two large breasts together to make a manageable roast. The duck is roasted to a rosy hue, just past rare, then sliced. Each “roast” is enough for four, so you will have leftovers. A drizzle of sweet aged balsamic vinegar is the only sauce it needs. Leftover duck is good cold for lunch, in a salad with lightly dressed arugula and toasted walnuts.