How to make
Peel the mushrooms and clean them. If they are large, cut them in half.
Put them in a suitable container for boiling and cover them with water. Add the vinegar, oil, salt and sugar.
Heat them until they come to a boil. Let them boil for about 5-6 min.
Remove the container from the stove, add the rosemary and leave them for about 30 min. to take in the marinade. Strain them and eat once cooled.
