RECIPE Sole-Wrapped Asparagus with Tangerine Beurre Blanc RELATED LINK Go to the Passover Plates feature that includes this recipe Go to our Passover page
There is nothing like a beurre blanc ("white butter") to give a piece of fish luster and dazzle. It is, in essence, a reduction of shallots and an acid (traditionally, vinegar or wine) balanced by the fresh creaminess of cold butter. Add the butter a little at a time (the most angst-free way to success), continuously whisk the mixture over low heat, and, voil�, you have a silky-smooth emulsion.
Variations on the theme abound; here and in the sole-wrapped asparagus recipe in our Passover Plates feature, we use tangerine juice as the acid to make a sunny-looking sauce with a springtime feel.
Beurre blanc has a reputation for being difficult: Like any element of high society, it's elegant but doesn't always behave. Think of it as the high-wire act of sauces. There's no safety net, so it's important to respect the technique. A few words of advice: Have all your ingredients ready to go, and don't leave the stove. When we say "whisk constantly," we mean it. Contrary to popular opinion, beurre blanc is a warm sauce, not a hot one, so never let it boil, or it will break. The broken sauce will still taste delicious, but that sublime texture will have been lost.
(1) When making the reduction, don't let the liquid reduce too much and be absorbed into the shallots.
(2) Butter, added a tablespoon at a time, is the only emulsifier.
(3) Whisk in each tablespoon of butter as the previous one begins to disappear.
(4) The end result is unctuous.