Step 1

Rinse duck breasts, pat dry with paper towels and rub with salt and pepper. Place skin-side down in a non-stick pan and cook over medium heat until browned, 5-7 minutes.

Step 2

Turn breasts and fry in fat until the undersides are brown, about 5 minutes. Transfer the meat to a plate and pour off the fat from the pan.

Step 3

Cut Mandarin oranges in half and squeeze. Pour the juice and the chicken stock into the pan and bring to a boil.

Step 4

Add duck breasts skin-side up and simmer, covered, on the lowest heat, about 40 minutes.

Step 5

Meanwhile, peel potatoes, rinse and slice on a vegetable slicer into thin slices. Arrange in a tile-like manner in 2 round gratin dishes (12 cm diameter) (approximately 5-inch diameter) in layers, seasoning each layer lightly with salt and pepper.

Step 6

Rinse cilantro, shake dry, pluck leaves and set some aside. Cut remaining cilantro finely and place in a bowl.

Step 7

Add vegetable stock and heavy cream, mix with the chopped cilantro and pour over the potatoes. Bake in preheated oven at 180°C (fan 160°C, gas mark 2-(approximately 350°F/convection 325°F) on the middle rack for 25-30 minutes. (If the top browns too quickly, cover with aluminum foil as necessary.)

Step 8

Meanwhile, rinse kumquats, drain and cut into slices.

Step 9

Take potato gratins out of the oven, cover with foil and keep warm. Put duck breast fillets in a small baking dish. Broil under the oven broiler until the skin is crispy, about 10 minutes.

Step 10

Meanwhile, let duck cooking liquid boil over high heat about 10 minutes to reduce to half the volume. Add kumquats and cook 3-4 minutes longer. Season with 1 pinch sugar, salt and pepper. Stir in crème fraîche.

Step 11

Cut duck breasts into slices and serve with the sauce on plates. Garnish with remaining cilantro and serve with cilantro potatoes.