Grind half the fish; you will have ⅔ to ¾ cup of purée. Set it aside. Following directions for fish filets in white wine, season the rest of the filets, arrange them in a buttered baking dish with the shallots, wine, and enough water barely to cover them. Bring to the simmer, cover with buttered paper, and bake in bottom third of oven for 8 to 10 minutes or until a fork just pierces them easily. Strain out all the cooking liquor, boil it down in an enameled saucepan until it has reduced to ¼ cup, and set it aside until later for your sauce mousseline sabayon.