Make the marinade: in a saucepan, pour water, vinegar, spices, salt, sugar. When you boil the marinade, add the mushrooms. After boiling the mushrooms, remove the foam and cook for 20-25 minutes. Remove from heat and quickly cooled, I poured in a basin of cold water and put the pot.
Spread the cooled mushrooms in a jar and put in the fridge. After 2 hours, season with onion, butter and Bon appetit!