Enriching with Butter and Cream

Liaison.

In addition to being a thickening agent, a liaison of egg yolks and cream is used to finish a sauce by giving it extra richness and smoothness.

Heavy cream.

Heavy cream has long been used to give flavor and richness to sauces. The most obvious example is adding cream to basic béchamel sauce to make cream sauce.

Butter.

A useful enriching technique, both in classical and in modern cooking, is called finishing with butter, or monter au beurre (mohn tay oh burr).

To finish a sauce with butter, simply add a few pieces of softened butter to the hot sauce and swirl them in until melted. The sauce should then be served immediately; if it is allowed to stand, the butter may separate.

Finishing a sauce with butter gives it a little extra shine and smoothness as well as adding to it the rich, fresh taste of raw butter.