Photograph: Maja Smend
Preheat the oven to 200°C, (fan 180°C), 400°F, Gas Mark 6. Using a long, sharp knife, score the skin on the duck breasts in a crisscross pattern. Rub the five-spice all over the breasts to evenly coat and then season them well with salt and pepper. Put them skinside down into a medium (ovenproof if you have one) frying pan. Place the pan on a medium heat and cook for about 8 minutes, without moving them, until the skin is crisp and golden and fat has rendered out.
Meanwhile, heat a small dry frying pan on a low heat and toast the cashew nuts for a few minutes, tossing regularly, until golden. Remove, tip them into a large bowl and leave to cool. Once the duck breasts are ready, turn them over so the skin is now up, drain off the fat and transfer the pan to the oven. If your pan doesn’t fit or is not ovenproof, then transfer the duck breasts into a small roasting tin. Cook them for 10 minutes for a pink finish (or another 5 minutes if you prefer them cooked through).
Meanwhile, mix together the dressing ingredients in a mug with a fork and set them aside to infuse. Toss the watermelon into the bowl with the cashews and add the spring onion, chilli, mint and coriander and leave aside also.
Once the duck breasts are cooked, remove from the oven and leave to rest and cool for 5 minutes. Then, halve them down their length and cut each piece into thin slices. Toss the duck through the salad along with the dressing until well mixed. Serve at once.
Cook’s tip: scoring the skin before cooking helps the fat to render (melt) out and make the skin nice and crispy.