I wanted to pump up the umami flavor of my classic hollandaise, so I added soy sauce, Worcestershire, and sherry vinegar. If I had pan drippings from a roast beef, I would whisk them in, too. I pair this with steak and garlicky fried potatoes.
Storage: This sauce is best eaten right after you make it, but you can hold it in the double boiler over very low heat or in a thermos for up to 1 hour. Refrigerate leftovers in an airtight container for up to 3 days.
In a small saucepan, melt the butter over medium heat. Don’t stir as it melts. You want the milky solids to fall to the bottom and the butter fat to float to the top. Keep warm.
In a small bowl, stir together the soy sauce, Worcestershire sauce, and a few dashes of hot-pepper sauce; set aside.
Pour water to a depth of 1-2 inches into a medium saucepan and place over medium heat. Rest a medium stainless-steel bowl in the pan over (not touching) the water. Put the egg yolks, vinegar, water, and ¼ teaspoon salt in the bowl and start whisking. As the bowl heats up, the yolks will begin to thicken. Whisk vigorously, scraping around the bowl with a heat-resistant rubber spatula from time to time so that bits of yolk don’t get stuck and overcook. Beat until thick and frothy but not quite fluffy, 3-4 minutes. The whisk will start leaving a clear space on the bottom of the bowl. Remove the bowl from the heat and whisk for another 30 seconds or so to stabilize the sauce and let the bowl cool down.
Continue whisking as you slowly drizzle in the warm melted butter, taking care not to add the milky-watery layer from the bottom of the pan. As you pour and whisk, make sure the yolks are accepting the butter and the yolks and butter are emulsifying. If the sauce looks at all broken or "curdly," stop adding butter and just whisk for a few seconds. Only resume adding butter once you’ve whisked the sauce into creaminess again.
Once all of the butter has been added, whisk in the soy sauce mixture and lemon zest. Taste and adjust the seasoning with salt and vinegar if needed. If possible, serve right away.
Variation: Fold in 2 tablespoons of chopped fresh tarragon with the lemon zest.