Cut seitan into slices of about 1 cm thickness. Rinse cold in a sieve and dab dry. Crush the spice mixture in a mortar. Mix with 4 tablespoons olive oil, 1 tablespoon sesame oil and 1 teaspoon salt. Mix with seitan.
Allow to steep for at least 30 minutes.
In the meantime, preheat the oven (electric cooker: 250 °C/circulating air: 225 °C/gas: see manufacturer). Wash the potatoes thoroughly, brush them off if necessary and cut them with the skin lengthwise into slices. Mix with 2 tablespoons olive oil and 1 teaspoon salt.
Pour into a flat roasting pan or onto a tray. Bake in a hot oven for about 30 minutes.
For the dip, mix quark, yoghurt and 1 tablespoon of olive oil. Wash the cucumber, cut in half lengthwise, remove seeds and dice finely. Wash mint, shake dry, chop leaves finely. Peel and finely chop the ginger.
Stir the cucumber and mint into the quark. Season to taste with salt, pepper and nutmeg.
Peel and finely dice the shallots. After about 30 minutes mix into the potatoes. Bake for about 15 minutes more.
Roast the black cumin in a pan without fat. Take out. Heat 2 tablespoons of sesame oil in the pan. Fry the marinated seitan in the oil over high heat for about 2 minutes on each side. Turn down the oven temperature.
Keep Seitan warm in it until everything is fried.
Sprinkle black cumin over the potatoes. Arrange everything. Serve with salad.