Separate legs from the breast by cutting where the breast and carcass end and legs begin, or have your butcher cut it for you. Using a sharp boning knife, follow right along the breast bone on either side and remove both breasts. Trim fat along outside of the breast allowing approximately one third of an inch of fat overlap. Score fat on breast by making a diagonal cut, making sure not to cut the breast meat. About four strokes is sufficient.
In a food processor, dice unpeeled ginger and garlic until coarsely chopped. Place in a stainless steel bowl. Add remaining ingredients. Place the two whole duck legs and the four duck breasts in the marinade. Remove the duck breasts after one hour. The legs should continue to marinate for an additional half an hour, and then be removed.
Preheat oven to 350 degrees.
Using the carcasses of the duck, place the duck legs on the duck carcass. Place legs and carcasses in a roasting pan and roast for 1 hour and 45 minutes to 2 hours. Check periodically to make sure the ducks are not getting too dark. They are ready when the leg wiggles freely to your touch, and they are a nice deep amber color. The skin should look crisp and rendered of fat. Cool. Once cooled, take your boning knife and cut through the skin right in the middle of the legs. Using your hands, separate duck legs. (Use your thumb to get under the oyster and gently pull leg from the bones.) Gently use your fingers to pull out the thigh bone. Trim legs a little to keep a nice triangular shape.
For the breasts:
Heat a large, 12 inch sautepan to medium high. (You can cook two duck breasts in one pan or cook one at a time in a smaller, 10 inch pan.) Add two breasts, skin side down to start rendering the fat. Cook over medium high heat for a couple of minutes. (You will need to remove the rendered fat as you go. Hold duck breast still with a pair of tongs and pour fat into a stainless bowl or other container. Return to heat). After the first couple of minutes on medium high heat, turn burner down to medium, so not to burn the duck. The duck should be a rich amber color. Continue cooking until the fat is almost completely rendered. You can check this by looking at the incisions of the fat. When there is only a thin, crisp skin, the duck is ready to be flipped. Turn duck over. Shut heat off and leave the breast to sit in the pan for about three to four minutes. Remove from pan and allow to rest for five minutes.
Meanwhile, place the duck legs in a medium to medium small saute pan, skin side down and pan covered to heat and finish any additional rendering of fat, approximately five minutes.
Slice duck breast into fairly thing slices, keeping the nice shape of the breast. With a spatula, pick up breast and fan it out onto the plate. Place duck legs on an angle near the top of the slices. Serve with Whipped Taro Root, Taro Chips, lots of julienned scallions and a little Duck Jus.
Peel taro root. First, for the chips, take your peeler and peel approximately one cup of long taro shreds. Reserve for frying.
Take the remaining taro and cut it up into rough 2 inch chunks. Place in a sauce pan, covering with cold water. Boil root until tender. Strain into a colander, reserving cup of the liquid. In a food processor, pulse taro, adding little dabs of butter as you go, along with some of the cooking liquid to make a smooth consistency. Remove and season with salt and pepper.
For the chips:
Heat a couple of cups of peanut or grapeseed oil to 350 degrees. Drops shreds into oil in small batches. Remove when crisp (the chips should still be light in color) and salt.
In a heavy bottom sauce pan, heat oil. Add chopped duck body, leek, celery and carrot pieces and cook until vegetables are golden. Add white wine and chicken stock and reduce by half. Add soy marinade, cooking an additional few minutes. Skim off any fat and strain.