Sauce Beurre Blanc (French White Butter Sauce)

Beurre blanc is a simple butter-based emulsified sauce that's great with fish or seafood. When compared to mother sauces such as velouté, which has been around since at least the 1600s, beurre blanc is a relative newcomer (and not a culinary mother sauce). It originated in the 1890s in Nantes, a city in western France close to the Atlantic coast and was originally called beurre Nantes. 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. Historical anecdotes aside, sometimes folks confuse these two sauces. Béarnaise uses liquid clarified butter, and it is important to keep it warm. With beurre blanc, on the other hand, you use whole butter, and it's important to keep it as cold as possible. This means that in addition to forgetting the egg yolks, our storybook chef also inadvertently used ice-cold butter instead of warm. You can see how improbable the origin story is. Beurre blanc tastes velvety and rich thanks to butter, but it's also slightly sweet and tangy as well. It pairs beautifully with fish and seafood. Good wines for the reduction include Chablis, sauvignon blanc or chardonnay, but any drinkable dry white will do.

1 lb unsalted butter, cold
1 cup dry white wine
½ cup white wine vinegar
1 Tbsp. shallot, finely chopped
kosher salt

Cut the butter into medium (½") cubes and return them to the refrigerator to keep them cold.

Heat the wine, vinegar, and shallots in a saucepan over high heat until the liquid boils. Continue boiling until the liquid has reduced down to about 2 Tbsp., about 30-40 minutes.

Reduce the heat to low, take the cubes of butter out of the fridge and start rapidly whisking them in, one or two at a time, to the reduction. As the butter melts and incorporates, add more and keep whisking. Continue until you only have 2-3 cubes remaining. This process should take about 25-30 minutes.

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.

Makes 9 (2 oz) servings.

Why Did My Beurre Blanc Spilt?
If you make this sauce correctly, it will be thick, creamy, and velvety. If it looks like melted butter, the emulsion has broken. This can happen for several reasons. Either the butter was not cold enough, you added the cubes too quickly, you didn't whisk hard enough, or possibly all three. To fix a broken sauce, simply take it off the heat and whisk in a few chips of ice until the emulsion comes back together.

Variation:
For a deliciously luxurious beurre blanc, try making it with leftover Champagne.