Credit: André BaranowskiThis classic French sauce brings together emulsified butter, egg yolks, and herbs.
MAKES ABOUT 2 CUPS
1/4 cup white wine vinegar
1/4 cup dry white wine
1 large shallot, finely chopped, about 1/4 cup
1 tsp. dried tarragon
3 stems tarragon, leaves stripped and reserved, stems chopped
10 black peppercorns
8 egg yolks, beaten
1 cup butter, melted
kosher salt to taste
pinch of cayenne pepper
1 tsp. fresh lemon juice
1. Put vinegar, wine, shallots, dried tarragon, chopped tarragon stems, and peppercorns into a large skillet over medium-high heat and simmer until reduced to 2 tbsp., about 5 minutes. Strain the reduction through a fine sieve; set liquid aside. Finely chop the reserved tarragon leaves.
2. Fill a medium pot with 2 inches of water and bring to a simmer over medium heat. To create a double boiler, rest a large bowl over the medium pot so that the bottom is close to the water but not touching it. Add the wine reduction to the bowl, then stir in the egg yolks, butter, salt, and cayenne pepper, whisking constantly until a thick sauce has formed, about 2-3 minutes. (Don't be alarmed if the mixture breaks or looks curdled; keep whisking and proceed with the recipe.) Continue whisking while pouring in 1/4 cup warm water, until the sauce is smooth.
3. Remove the bowl from the heat, stir in lemon juice and chopped tarragon leaves, and adjust seasonings. Keep warm until ready to serve. If the sauce thickens, you may whisk in additional warm water until it reaches the desired consistency.