Cook halibut in boiling salted water, drain, and rub through a sieve. Season with salt, cayenne, and lemon juice; add cream beaten until stiff, then beaten whites of eggs. Turn into small, slightly buttered moulds, put in a pan, half surround with hot water, cover with buttered paper, and bake twenty minutes in a moderate oven. Remove from moulds, arrange on a serving dish, pour around Béchamel Sauce or Lobster Sauce II, and garnish with parsley.