Filet de Haddock Poché sur Lit de Choucroute, Beurre Blanc. - A filet of poached smoked haddock served on abed of choucroute with a beurre blanc sauce. Here the use of the English name for haddock on a French menu indicates smoked haddock. For more about French butter sauces see the post: The Butter Sauces on Your Menu. Three of France's Popular Butter Sauces.