Guests rave about this Northwest-inspired dish, developed as part of Holland America Line’s Signature of Excellence initiative. Plank cooking imparts a subtle smoky flavor, which provides an intriguing counterpoint to the elegant crab topping.
Place cedar plank in sink and cover with water, weighing it down with a can or small pot to keep it submerged. Let soak 1 hour. Preheat oven to 425°F. Drain cedar plank and place in oven for 10 minutes. The plank will begin to crack and smoke (this is normal).
Season halibut fillets with salt and pepper and sprinkle with thyme. Place halibut directly onto cedar plank and roast until fish is just opaque in the center, 10 to 15 minutes. Remove plank from oven and remove halibut from plank.
To serve, heat butter in a small heavy skillet over moderate heat until foam subsides. Add crab meat and claws and heat through, stirring gently, about 2 minutes. Top halibut with crab meat and garnish with crab claws and asparagus. Spoon some sauce over the fish and crabmeat and serve the remaining sauce separately. Garnish with thyme.
Note - Cedar planks are readily available in packages from kitchen stores, or can be cut to your specifications at home centers. Buy 3/4-inch thick untreated cedar at your local home center and have it cut to fit inside of a pan that is 13 inches x 9 inches; the pan will catch any drips while cooking. Soaked planks that are 1 inch thick can also be used directly on your outdoor grill.
In a small saucepan, combine shallot, peppercorns, tarragon, and both vinegars. Bring to a boil and cook until almost evaporated. Remove from heat and add water.
Transfer tarragon mixture to a double boiler and whisk together with egg yolks. Place the double boiler over (but not touching) boiling water and whisk constantly until mixture forms thick ribbons. While whisking constantly, add butter, little by little, waiting for each addition to be incorporated before adding any more, until sauce triples in volume. Do not overcook sauce; it should be warm but not hot. (You may need to remove the bowl from the water, from time to time, if the sauce gets too hot.)
Strain to remove any cooked egg particles, if necessary. Whisk in herbs and season with salt and pepper.
Note - To clarify butter, melt 1 cup unsalted butter in a medium saucepan over low heat. Cook until the butterfat becomes clear and milk solids drop to the bottom of the pan. Skim the surface foam as the butter separates. Carefully spoon the clear butterfat into a measuring cup. Discard the milky liquid at the bottom of the saucepan.