To prepare the duck breasts, lightly score the duck breasts’ skin with diamond cuts.
Rub with the five-spice and then season with the salt and pepper. Set aside.
Meanwhile, preheat the oven to 325°F. In a dry oven-proof sauté pan heated over medium heat, put the duck breast skin side down. The duck skin has plenty of fat that we don’t need to add cooking oil here.
Once you hear a little sizzling sound from the duck skin, lower the heat to medium-low.
Render the fat over medium-low heat for 5 minutes.
When the skin is light gold, baste the meat with the duck fat in the pan, then place the pan in the oven for 7 minutes. Make sure the duck breasts are skin side down when you place them in the oven.
When done, allow the meat to rest for 2 minutes. The duck will be medium at this point. If you would like your duck to be more cooked, you can leave it in the oven for 2 minutes longer.
To plate, slice the duck breasts and spoon a generous amount of kumquat mustard on the plate. Place the sliced duck, skin side up, on top of the mustard, and add sugar snap peas around the plate.