How to Make It
Melt the butter in a saucepan with a bit of a lip, swirling the butter in the pan regularly. Meanwhile, put an inch or two of water in another saucepan, and set a heatproof bowl over the top. (Ideally, use a stainless steel or glass bowl—an aluminum bowl can discolor your sauce.) Set this double boiler over a medium-low flame.
Crack 2 egg yolks into the bowl, add the salt, lemon juice, and water, and whisk well, until the yolks have slightly lightened in color. Remove the double boiler from the heat while you very slowly add the melted butter—1 tablespoon at a time at first, then more quickly, whisking enthusiastically all the while. Return to the heat and continue whisking until the mixture has fully come together. It should be a pale buttery yellow, thick enough to coat a spoon, and completely smooth. Taste for seasoning; add a little black pepper and/or smoked paprika (especially nice if you’re a vegetarian and not serving this over smoky Canadian bacon or ham), and a little squeeze of fresh lemon juice if you like. Whisk together well.
At this point, the sauce is ready. Remove the double boiler from the heat and spoon it over steamed asparagus, dip artichoke leaves into it, or use it as an egg Benny’s crowning glory.
For eggs Benedict for 4 people, fry or bake bacon (classically, Canadian bacon) if you’re serving meat eaters; slice up some avocado or sauté some spinach with a bit of garlic. Lightly toast 4 English muffins—too crispy and they’re hard to cut. Meanwhile, poach 4 to 8 eggs (up to 2 per person). Here’s how. To assemble, lay the bacon or avocado or what have you onto the toasted muffin, carefully set a patted-dry poached egg onto each muffin half, and carefully spoon over each egg.