Trim the visible fat and silver-skin from the flesh side of the duck. If the tenderloins are still on the breasts, leave them on. Don’t trim the skin side; simply score the duck skin in a crosshatch pattern to allow the fat to cook out. Mix the five-spice powder with the salt and pepper in a small bowl. Gently rub the duck all over with the mixture.
Heat a 12-inch skillet over medium-low heat and put the duck, skin side down, in the skillet. Slowly render the fat from the skin without moving the duck breasts. After 15 minutes, tilt the pan and carefully spoon off as much fat as possible. Cook until the skin is dark golden brown and crisp, about 25 minutes total.
Flip the breasts with a metal spatula (carefully loosen the skin if it’s stuck to the pan). Increase the heat to medium and finish cooking the duck until the second side is golden and the duck is done to your liking, another 3 to 7 minutes, depending on thickness. (An instant-read thermometer should register 135°F for medium doneness, which will still be pink and juicy.)
Transfer the duck breasts to a cutting board and let rest, skin side up, for about 5 minutes before serving either whole or sliced on an angle into medallions.
This duck goes nicely with a wild rice pilaf with toasted almonds and sautéed Asian greens seasoned with a touch of sesame oil.