Use this hollandaise sauce to top our Steamed Artichokes with Poached Egg and Smoked Salmon.
Whisk yolks in a large heatproof glass bowl until they begin to turn pale, about 1 minute. Whisk in 4 1/2 teaspoons warm water. Set bowl over a pan of barely simmering water; heat yolk mixture, whisking vigorously, until thickened, 2 to 3 minutes (do not overcook). Remove bowl from pan. Whisk in lemon juice.
Whisking constantly, pour in melted butter, one drop at a time at first, leaving milky solids behind; whisk until thickened. Season with salt. If not serving immediately, pour hot water from pan into a separate (cool) pan; set bowl on top. Keep sauce warm, whisking occasionally, up to 30 minutes. If sauce becomes too thick, whisk in warm water, 1 teaspoon at a time, to thin.
The yolks in this sauce are not fully cooked; it should not be prepared for pregnant women, babies, young children, the elderly, or anyone whose health is compromised.