This popular Hangzhou dish with a sweet and sour flavor is traditionally made with cleaned grass carp that is poached or steamed with ginger, then covered with a sauce consisting of black vinegar, brown sugar, soy sauce, corn flour, water, and stock.
When served, the fish is usually topped with sesame oil and finely chopped spring onions. Some sources date West Lake vinegar fish to the Southern Song Dynasty (1127-1279), when it was supposedly prepared by a woman named Sister Song in her restaurant near the West Lake.