How to Make It
In a large enameled cast-iron casserole, combine the water with the onion, ginger, coriander and salt. Cover and bring to a boil. Reduce the heat to low and simmer, covered, for 15 minutes. Increase the heat to high and add the fish. Cover and bring back to a boil. Remove the casserole from the heat and let the fish poach in the aromatic liquid for 10 minutes.
Meanwhile, in a small bowl, combine the soy sauce with the chicken stock, sesame oil, vinegar, sugar and white pepper.
Using 2 large spatulas, transfer the fish to a platter. Pour the sauce over the fish, sprinkle with the red cabbage and serve.