Peel and wash the potatoes and cook in salted water for about 20 minutes. Clean, wash and cut the leek into rings. Mix vinegar, flour and about 2 l water. Mix black salsifies under running water.
Brush off the water, peel and cut into pieces. Immediately put water in the vinegar so that they do not discolour.
Heat 2 tablespoons of oil. Sauté the leek and black salsify for about 5 minutes. Add almost 100 ml water and stock. Bring to the boil, cover and simmer for about 8 minutes.
Drain the potatoes, let them cool down a little and cut them into slices. Fold into the black salsify. Season to taste with salt, pepper and nutmeg.
Wash the salmon, dab dry and cut into 4 pieces. Season with salt and pepper. Press one side of the fish in sesame seeds. Heat 2 tablespoons of oil. Fry the fish with the sesame seeds side first for 2-3 minutes. Then turn and fry for about 2 minutes.
Serve with black salsify potatoes and vegetables.