So things are about to get a bit crazy! After two minutes and your Roux (name for the butter/flour mixture) is golden and beautiful, add the 1 1/3 cup of warm milk. Continue to stir until you see the VERY VERY VERY first signs of it boiling. When this happens immediatly take it off the heat and continue to stir.
In a separate bowl prepare the 4 egg yolks and stir the egg yolks together in that bowl until they are creamy.
