This flavorful Chinese-style dish with its rich mahogany sauce can be prepared in a wok if you prefer. Be careful not to add too much salt in the sauce; some soy sauces and sherries are saltier than others.
2 pounds haddock or other firm-fleshed fish fillets
2 tablespoons cornstarch
2 tablespoons peanut oil
1 scallion or 1/2 medium onion, chopped
3 cloves garlic, crushed
1 slice ginger, cut in thin strip
Cut fillets into 2-inch and 3-inch pieces. Coat with cornstarch. Heat a large skillet (or wok, if you prefer) to 350 degrees F. Add oil, heat thoroughly. Fry fish on both sides until golden brown.
3 tablespoons soy sauce
2 tablespoons sherry
1/2 cup brown sugar
4 tablespoons vinegar
2 tablespoons cornstarch
1 cup chicken stock
1 teaspoon salt, or less to taste (optional)
While the fish is cooking, combine the sauce ingredients in a small bowl. Set aside. Remove the fish from the pan and quick-fry scallion, garlic, and ginger until golden brown. Add the sweet-sour sauce and bring to a boil. Stir constantly until thick. Reduce the heat to low. Add the fish gently into the sauce and simmer for 1 minute. Serve hot.