Beurre blanc is a simple butter-based emulsified sauce that's great with fish or seafood. It's a relative newcomer to the culinary repertoire, having originated in the 1890s in the city of Nantes, situated on the Loire river in the western part of France close to the Atlantic coast.
Compare this with sauces like velouté, which has been around since the 1600s at least.
According to the legend, a chef named Clémence Lefeuvre (or in some tellings, her assistant) was making béarnaise sauce but forgot to add the egg yolks. This is about as likely as hamburgers being invented because a chef tried to make steak tartare but accidentally cooked it.
Which is why it's a good idea to take these culinary origin stories with a grain of salt. Oddly enough, béarnaise sauce is itself the subject of an origin story based on the idea that it, too, was invented by mistake. I don't quite understand the appeal of anecdotes attributing these creations to sheer error. If I'd invented béarnaise or beurre blanc, I'd be taking full credit for it.
Another difference between béarnaise and beurre blanc is that with béarnaise we use liquid clarified butter, and we want it to be warm. With beurre blanc, on the other hand, we use whole butter, and it's important to keep it as cold as possible. So you can see how improbable the origin story is.
In any case, we know it was Clémence, and we know that she served her beurre blanc sauce (or beurre Nantes, as it was known then) with fish.
Good wines for the reduction (or au sec, meaning "nearly dry") include Chablis, Sauvignon Blanc or Chardonnay, but any drinkable dry white will do. For a deliciously luxurious beurre blanc, try making it with leftover Champagne.
Note that if you make the sauce correctly, it will be thick and creamy and velvety. If it looks like melted butter, the emulsion has broken, most likely because your butter wasn't cold enough, or you added the butter cubes too quickly, or you didn't whisk hard enough, or possibly all three. If that happens, take it off the heat and whisk in a few chips of ice until the emulsion comes back together.
You can also make a variation called before rouge ("red butter"), by substituting red wine and red wine vinegar in the reduction.
- 1 cup dry white wine
- ½ cup white wine vinegar
- 1 Tbsp finely chopped shallot
- 1 lb unsalted butter, cold
- Kosher salt, to taste
- Cut the butter into a medium (½-inch) cubes and return the butter cubes to the refrigerator to keep them cold, which is very important.
- Heat the wine, vinegar, and shallots in a saucepan until the liquid boils, then lower the heat a bit and continue simmering until the liquid has reduced down to about 2 tablespoons. This should take about 10 minutes.
- Once the wine-vinegar mixture has reduced to 2 tablespoons, reduce the heat to low, take the cubes of butter out of the fridge and start adding the cubes, one or two at a time, to the reduction, while you whisk rapidly with a wire whisk.
- As the butter melts and incorporates, add more butter and keep whisking. Continue until you only have 2-3 cubes remaining. Remove from heat while whisking in the last few cubes, and whisk for a moment or two more. The finished sauce should be thick and smooth.
- Season to taste with Kosher salt. Traditionally the shallots would be strained out before serving, but doing so is optional. Serve right away.