These halibut steaks topped with a delicate mirepoix are exquisite as they are, but the caviar garnish gilds the lily. The dish is named after the port city of Astrakhan on the Volga River, not far from the Caspian Sea, where much of the famed Russian caviar is processed.
Prepare a mirepoix: Mix together the onion, green beans, carrot, mushrooms, salt and pepper. Place the vegetables in an ovenproof dish and dot them with the 2tablespoons of butter. Cover and bake at 350°F for 30 minutes.
Place the halibut steaks in a large, shallow, ovenproof dish. A