Steam washed Romaine leaves for 2 minutes until bright green; cool in ice water. Set aside.

Clean mushrooms thoroughly and blanch in salted water 3-4 minutes. Dice coarsely; set aside.

Heat butter or margarine in skillet and saute mushrooms, onion and crab meat until onion is just soft; lightly season with salt and pepper. Let cool; separate into 6 equal portions.

Place 2 Romaine leaves on counter, overlapping each other. Place 1 fillet of halibut on top; cover with 1 portion of crab filling.

Fold edges of Romaine up and around fish and roll to cover totally; tightly wrap lettuce roll in plastic wrap. Refrigerate until ready to cook. Repeat with other leaves and filling.

Steam rolls 15-20 minutes; remove plastic film and slice each roll onto a dinner plate. Serve with your favorite white wine sauce, lobster sauce or herb sauce.