Place skillet over medium heat and melt butter. Add flour and cook blond roux, stirring, for about a minute.
Add scallions, the white part. Cook stirring for a minute.
Add chopped oysters. Cook stirring for a minute.
Add chopped shrimp. Cook stirring for a minute.
Now, we add liquids one by one, cooking them done and thickening the sauce. First, add oyster liquor, stir and cook. Then repeat with white wine, then heavy cream.
Season to taste with salt, pepper, add cayenne pepper if you like the heat, add hot Louisiana sauce adjusting the amount to your taste. Cook stirring.
Turn off the heat and add egg yolks. Stir to mix well.