Yield: 6 servings.
1 pound medium asparagus
2 tablespoons extra-virgin olive oil
¼ teaspoon kosher salt
¼ cup fresh chives, chopped
3 egg yolks
1 tablespoon water
2 tablespoons fresh lemon juice
2 sticks unsalted butter, softened
½ teaspoon salt
½ teaspoon freshly ground white pepper
1 dash cayenne pepper
Preheat oven to 425°. Trim approximately 2 inches from the woody ends of the asparagus. Spread the asparagus in a single layer on a parchment-lined baking sheet. Drizzle with olive oil, sprinkle with salt, and roll to coat each spear thoroughly. Roast the asparagus until the spears are just tender and the tips begin to lightly brown, about 8 to 10 minutes. Sprinkle chives over asparagus and toss lightly. Spread the roasted asparagus on a serving platter.
For the sauce: Whisk the yolks, water, and lemon juice in a saucepan for a few moments, until thick and pale yellow. Set the pan over low heat and continue to whisk, making sure to get all over the bottom and insides of the pan. Move the pan off the burner for a few seconds, and then back on. Whisk continuously until the eggs become frothy and increase in volume, and the sauce begins to thicken. Remove from the heat. Add softened butter a teaspoon at a time, whisking constantly to incorporate each addition. As the emulsion forms, you may add the butter in slightly larger amounts, always whisking until fully absorbed. Continue incorporating butter until the sauce has thickened to the desired consistency.
Season lightly with salt, white pepper, and a dash of cayenne pepper, whisking well. Taste and adjust the seasoning, adding drops of lemon juice if needed. Serve lukewarm.