Boil the lobsters for 15 minutes in salted water. Drain, then cut in half with a sharp knife, inserting the point into the back and cutting first backwards then forwards (carefully!). Remove the meat from the tail and claw, and reserve the shell.
Chop the lobster meat into pieces about the size of the end of your finger. Chop the mushrooms slightly smaller.
In a heavy skillet, melt the butter and sautee the green onions. Stir in the flour thoroughly, and cook over low heat for about three minutes.
Add the brandy and let it boil for about two minutes. Add the cream, salt, and cayenne. Bring to a light boil, whisking to blend.
Beat egg yolks with 2 Tbs. water. Stir quickly into the sauce.
Add the mushrooms, agitating the pan to cover them completely with the sauce. When the mushrooms are soft, add the lobster and heat through.
Spoon the mixture into the lobster shell and top with bread crumbs. Run the filled shells under the broiler until the contents bubble and the bread crumbs brown.
