Preparation / Directions:
Court Bouillon: Peel the carrot and cut into thin slices. Cut celery and onion into thin slices. In a non-reactive pot, combine all of the ingredients; bring to a simmer, cover, and cook for 20 minutes. You should have about 3 cups. Court Bouillon can be made several days ahead, or it can be frozen.
COOKING AND SERVING: Bring Court Bouillon to a simmer. Put the fillets, skin side down, into the simmering liquid, lower heat, and poach gently until fish is just cooked through, about 5 minutes. Remove fish from the liquid, peel off the skin, and cover to keep warm.
Strain the Court Bouillon and put 1/4 cup into a small saucepan. Reserve remaining bouillon for another use. Add wine and vinegar to the saucepan and bring to a boil; boil about 3 minutes until liquid is reduced to 2 tbs. Over the lowest possible heat, whisk in the butter a bit at a time.
The butter should soften to make a creamy sauce but should not melt completely. Stir in the chives, parsley, tarragon, and lemon juice. Season to taste with salt and pepper. Serve the fish topped with the sauce.
NOTE: The Herb Butter Sauce here is a variation of the traditional French beurre blanc. The sauce is rich and powerful, yet also subtle enough so that it won't overpower the delicate taste of the poached fish. The trick to making this sauce is to emulsify the butter without melting it, so that the sauce is creamy. The acid in the wine and vinegar aid in the emulsification. Whisk in the butter, a tbs at a time, over the lowest possible heat, moving on and off the heat as necessary