Clean, wash and cut the peppers into strips. Clean the mushrooms and cut them into pieces. Heat the fat in a pan. Fry the bell peppers and mushrooms for 5 minutes. Wash the chives and cut them into small rolls, except for a little garnish.
Mix vinegar, chives, salt, pepper and sugar. Whip the oil into the mixture. Arrange peppers and mushrooms on plates. Pour marinade over them and serve garnished with chives.