Transform & Preserve

Liaison

Thicken and enrich a sauce with an egg-yolk-and-cream blend

A liaison is a mixture of egg yolks and cream whisked into a sauce or soup at the end to thicken and enrich it with velvety body. It's a classic finish for veloutés and blanquettes. Temper it with a little hot liquid first and never let the sauce boil after, or the yolks scramble.

A liaison is the classical French finish that thickens and enriches a sauce or soup with a blend of egg yolks and cream. Whisked in at the very end, the yolks lend velvety body and a luxurious sheen, while the cream rounds out richness — it's the silky crown on a velouté, a blanquette de veau, or a delicate soup. Because raw yolks scramble if shocked with heat, a liaison must be tempered with a ladle of the hot liquid first, then stirred back in over low heat that never reaches a boil. It's a small step with a high ceiling for both elegance and disaster.

Difficulty: Advanced

Types & varieties

Classic velouté liaison

Yolks and cream finishing a velouté or fricassée sauce for silkiness.

Blanquette finish

The traditional egg-and-cream enrichment of a white veal or chicken stew.

Soup liaison

Yolks and cream to give body and richness to delicate soups.

How to do it

1
Whisk the liaison
Beat together egg yolks and cream in a bowl until smooth and uniform.
2
Temper it
Slowly ladle in some of the hot sauce or soup while whisking, warming the yolks gradually so they don't scramble.
3
Stir back in
Pour the warmed liaison back into the pot, whisking it through the rest of the liquid.
4
Heat gently
Warm over low heat, stirring constantly, until the sauce thickens and turns velvety.
5
Watch the temperature
Stop well before a simmer; boiling will curdle the yolks and ruin the finish.
6
Serve promptly
Once thickened and glossy, serve right away — a liaison-finished sauce won't tolerate reheating to a boil.

The science

Egg yolks thicken by gentle protein coagulation: as they warm, their proteins unfold and gently set, lending body without the floury feel of a starch thickener. The cream raises the threshold a little and adds richness. The danger is that yolk proteins coagulate fully — scramble — at temperatures well below boiling, so tempering (gradual warming) and a strict no-boil rule are what keep the sauce smooth instead of grainy.

Common mistakes

A liaison is one of the more failure-prone finishes.

Adding the cold liaison straight into hot liquid without tempering, instantly curdling the yolks.
Letting the sauce boil after adding it, which scrambles the eggs.
Reheating a finished sauce too aggressively, breaking it.
Using too many yolks for the volume, making it heavy and prone to curdling.