Romanian veal sour soup

This is a traditional Romanian (Moldova region) veal sour soup. It’s mandatory to use veal (milk-fed veal if possible) and not other type of meat as this will decide the taste of the soup. I like it very sour, but everybody can use less sour powder. Another mandatory and secret spice in lovage or “leustean”, but I don’t know where you can buy it except a Romanian grocery/produce shop.