Sift together the flour, salt, pepper, and cayenne into a broad bowl.
Separate eggs and combine the egg yolks and the milk in a small bowl.
Mix the whiskey, the Herbsaint, and both bitters in a glass to make a Sazerac in the rough (the finished cocktail would be sweetened with simple syrup and shaken with ice).
Heat the butter in a skillet.
Coat the oysters with the seasoned flour mixture, then dip them into the egg wash. Coat them again with the bread crumbs.
Saute the oysters in the butter until lightly browned. Then pour the Sazerac into the skillet and carefully touch flame to it. Let the flames die out and most of the liquid evaporate.
Serve the oysters topped with the green onions and moistened, if you like, with beurre blanc.
To make the beurre blanc, heat the cream over low heat in a saucepan until it comes to a boil. Cut in, bit by bit, all of the butter, whisking all the while. Remove from heat and whisk in lemon juice and pepper.