Trim wingtips and cut off the neck of duckling. Wipe the bird with a damp clean cloth inside and out, and sprinkle the cavity with salt and freshly ground black pepper.
Melt butter in a deep heatproof casserole just large enough to contain duckling, and sauté duck until golden on all sides. Reduce heat; cover and simmer gently for 45 minutes, turning duck from time to time. Add two-thir