Score the skin of 150 grams of duck breast in a crosshatch pattern, being careful not to cut into the meat. Season generously with salt and pepper (3 minutes).

Finely slice 200 grams of red cabbage (5 minutes). Peel, core, and chop 100 grams of apple (e.g., a tart variety like Honeycrisp or Granny Smith) into small pieces (3 minutes). Thinly slice 30 grams of onion (2 minutes).

Heat a dry oven-safe skillet over medium heat. Place the duck breast skin-side down in the cold skillet (no oil needed, the fat will render). Cook for 8-10 minutes, or until the skin is golden brown and crispy, pouring off excess fat as it accumulates (save this for cooking!).

Flip the duck breast and sear the meat side for 2-3 minutes. Transfer the skillet to a preheated oven at 180°C (350°F) and cook for another 5-7 minutes for medium-rare, or longer for desired doneness (7 minutes). Let the duck breast rest on a cutting board for 5-10 minutes before slicing (10 minutes).

While the duck rests, use some of the rendered duck fat (or 5 ml olive oil) in a saucepan over medium heat. Add the sliced onion and cook until softened, about 3-4 minutes.