Cut the buns in half horizontally. Roast on the cut surfaces in portions in a pan without fat for approx. 1 minute, let cool off. Rinse fillets with cold water, dab dry, season with salt and pepper. Heat 2 tablespoons of oil in a frying pan. Fry fillets on medium heat for 6-7 minutes on each side
Wash the asparagus and dab dry. Heat 1 tablespoon of oil in a frying pan. Sauté the asparagus for about 1 minute. Season with salt, pepper and sugar.
Peel onions and cut them into fine rings. Put chutney on the lower halves of the rolls and arrange fillets, onion rings and asparagus on top. Sprinkle with coarse pepper. Place the upper halves of the rolls on top