03Return the wok to a medium flame with 4 tablespoons of fresh oil. When it is hot, add the chili bean paste and stir-fry for 20 to 30 seconds until the oil is red and smells delicious. Add the ginger and garlic and stir-fry for another 20 seconds or so until you can smell their fragrance. Then pour in all the stock, turn up the heat, and bring the liquid to a boil. Season to taste with the sugar and soy sauce.04For the sauce: Gently place the fish into the wok and spoon some sauce over it. Turn the heat down, cover and simmer for 8-10 minutes until the fish is cooked and has absorbed some of the flavors of the sauce. Turn the fish once during the cooking time, spooning some more sauce over it.05When the fish is done, gently transfer it to a serving dish. Add the cornstarch mixture to the sauce and stir briefly until it thickens. Add the vinegar and scallions, stir a couple of times, and pour the sauce over the waiting fish.