For me the only technique that makes them tasty is steaming. Everything else seems to produce a dry, tough texture. I usually fillet and remove skin rather than leave whole (you can use a much smaller pot then too). I've used fresh brown mushrooms or even skipped them if Chinese mushrooms are not available. It's actually a really easy dish and very forgiving in terms of timing / doneness which a lot of fish recipes are not.
Steamed Rock Cod
This recipe from "Wisdom of the Chinese Kitchen" by Grace Young (Simon & Schuster, 1999) captures the spirit of "Crouching Tiger, Hidden Dragon." If rock cod is unavailable you may substitute rockfish, red snapper, black sea bass or small striped bass.
2 rock cod (1 1/2 pounds each), cleaned and gutted, with head and tail intact
1 1/2 teaspoons salt
4 Chinese dried mushrooms
1 1/2 teaspoons finely minced garlic
3 tablespoons finely shredded ginger
2 scallions, finely shredded
1 tablespoon Shao Hsing or other rice cooking wine
1/2 teaspoon sugar
2 teaspoons vegetable oil
2 tablespoons thin soy sauce
Cilantro sprigs for garnish
Thoroughly rinse fish in cold water and drain. Gently rub cavity and outside of the fish with salt and rinse again. Place fish on a rack and allow to air dry.
In a medium bowl, soak mushrooms in 1/4 cup cold water for 30 minutes or until softened. Drain and squeeze dry. Reserve remaining mushroom liquid to flavor soups. Cut off and discard stems and thinly slice the caps.
Place fish on heat-proof oval platter with sloping sides. Trim tail so fish fits onto platter. Evenly sprinkle mushrooms, garlic, ginger and half the scallions on fish. Drizzle with rice wine and sprinkle with sugar.
Set a cake rack in a 14-inch skillet; pour in 1/2 inch of water. Cover skillet; bring water to boil over high heat.
Carefully place platter into steamer; cover and steam 13 to 15 minutes on high heat or until fish flakes when tested.
Check water level and replenish with boiling water, if necessary. Test fish for doneness by poking the thickest part with a fork or chopstick.
Flesh should flake. If not, steam for 1 to 2 minutes longer or until fish just flakes.
Remove skillet from heat; carefully remove platter from steamer.
Pour off any liquid in platter.
In a small skillet, heat oil over high heat until hot but not smoking; sprinkle remaining scallions over fish; drizzle with soy sauce.
Carefully pour hot oil over fish. The oil will make crackling sound as it hits the fish. Garnish with cilantro. Serve immediately.
Serves 4.
Per serving: 287 calories; 6.6 g fat (1.2 g saturated fat; 21 percent calories from fat); 3.5 g carbohydrates; 91 mg cholesterol; 739 mg sodium; 50.5 g protein; 0.3 g fiber.