Sauce Allemande / Parisienne
The science
This is the system's bridge from starch-thickening to egg-thickening. The yolk-and-cream liaison must be tempered — whisked with a little hot sauce before being returned — and the sauce must never boil afterward, because yolk proteins coagulate and curdle above roughly 70–80 °C. Done right, the partially set yolk gives a richer, more velvety, slightly glossier body than roux alone, while the lemon both seasons and helps stabilize. That Carême ranked this technique as a mother shows how central egg-liaison thickening once was.
Flavor profile
Velouté (classically veal) finished with a liaison of egg yolk and cream, sharpened with lemon, off the heat.
Culinary uses
Base for Poulette and other refined white derivatives; vegetables, sweetbreads, poached white meats.
Reference notes
Parent: Velouté. Technique: liaison / tempering. Historical note: renamed Parisienne in WWI. Child: Poulette.
What goes wrong
Boiling after the liaison (curdling); adding yolks untempered (scrambling).