Put the mustard in mixing bowl and slowly whisk in 1 cup of the Vinaigrette. Whisk in the shallot. Put in a small saucepan and set aside. Bring the court bouillon to a boil in a 10-inch pot. Season the halibut with salt and pepper on both sides. Add the halibut to the pot and adjust the heat so the liquid just simmers. Poach until a metal skewer inserted into the center of the halibut meets only a little resistance and the skewer, when left in the fish for 5 seconds, feels barely warm when touched to your lip, about 5 to 6 minutes. The halibut should be rare (thinner steaks will be ready sooner). Take the steaks out ot the liquid as soon as they are done (discard the court bouillon). In a small saute pan with 1 tablespoon butter, saute leeks until tender. Meanwhile, add the herbs to the Vinaigrette and warm over low heat. Pull the skin off the halibut and place in the center of 4 plates. Spoon the Vinaigrette over and around the fish. Serve immediately, with steamed asparagus.
Whisk together the mustard, salt, pepper, and vinegars. Whisking constantly, very slowly drizzle in the olive oil and then the corn oil. Store, tightly covered, in the refrigerator for up to 1 week.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Eric Ripet, Le Bernardin, New York, NY