From Mastering the Art of French Cooking, Vol. 1. "in casserole roasting, the duck is browned on all sides, then set to roast in a covered casserole. Cooking in its own steam, the duck's flesh becomes wonderfully tender, and the layer of subcutaneous fat is even more effectively dissolved than by roasting. The turnips finish their cooking with the duc absorbing the cooking juices, are particularly succulent." I have made this duck many times and it is my favorite method. I serve it with this: http://www.recipezaar.com/243203 Note: A bouquet garni consists of 4 sprigs of parsley, 1/2 a bay leaf and 1/4 tsp dried thyme tied in washed cheese cloth.