Cook or saute' the chicken breasts until tender. Remove and debone. Cook the broccoli and season lightly, drain and set aside. Melt the butter, stir in the flour and add the chicken stock. Cook, stirring constantly, until the mixture comes to a boil. Simmer gently for about 5 minutes. Cool slightly, then beat in the egg yolks. Whip the cream (not too stiff) and fold it in with the sherry. Place the broccoli in the bottom of an oven proof dish. Cover the broccoli with half the sauce and then the grated cheese. Arrange the chicken over the cheese covered broccoli and top with the remaining sauce and additional cheese if desired. Bake at 180ºC or 20 minutes-just until very hot. If desired put it under the broiler for a minute to brown at the very end of the heating period. *This dish can be made ahead as it freezes well. Posted on PRODIGY, 0.021739130434783; formatted by Elaine Radis; PRODIGY, BGMB90B; GEnie, E.RADIS