Frozen halibut should be cooked without thawing as it tastes fresher than thawed fish. The secret to successful halibut cookery is to not overcook. Whichever of the following cooking methods you choose, your halibut will be cooked when the flesh becomes opaque but is still moist and can easily be pierced with a fork.
Place halibut in a greased baking dish, or wrap in oiled foil and place on a baking sheet. Brush with melted butter or oil and season with salt and pepper, or cover with a piquant sauce. Bake in a preheated 450°F (230°C) oven until done, about 10 minutes for each inch (2.5cm) of thickness.
Rinse halibut fillets or steaks and pat dry with a paper towel. Place fish on a rack above a baking dish, and brush with melted butter or oil. Preheat broiler and adjust oven rack so fish is 3 to 4 inches (7.6 to 10cm) from the element. Broil, turning once, until fish is opaque but still moist in the center, about 6 to 10 minutes, depending on size of the fish.
Halibut fillets or steaks may be placed directly on a greased grill; Greenland turbot should be supported by perforated aluminum foil. Grill 4 to 6 inches (10 to 15cm) above prepared coals or fire. Baste with butter, oil, or marinade and close hood of grill. Cook until fish is opaque and moist on the inside, about 6 to 8 minutes for fish less than 1-inch (2.5 cm) thick, and 10 to 15 minutes for fish larger than 1-inch (2.5cm) thick.
Coat halibut with seasoned flour, crumbs, or cornmeal. Shake off any extra coating and fry in a small amount of hot butter or oil, turning once halfway through cooking time. Cook until opaque and moist on the inside, 4 to 8 eight minutes.
Pour oil into a wok or deep fryer; it should be at least 1 1/2inches (3.8 cm) deep, and the cooker should be less than half full of oil. Heat oil to 375°F (190°C), using a thermometer to monitor temperature. Cut boneless strips into similar sized pieces about 1 1/4 to 1 1/2-inch (3.175 to 3.8 cm) thick. Dip in batter, drain, and then slip pieces into hot oil. Cook until brown, 2 to 3 minutes.
Bring poaching liquid, consisting of water, broth, and herbs and spices, to a simmer. Slip the halibut in, then cover pan and keep liquid at a simmer for about 8 minutes per inch (2.5cm) of thickness.