We’re all becoming more health conscious, and making hollandaise with olive oil instead of butter results in an equally rich sauce. You can flavor the hollandaise with any citrus fruit—grapefruit or orange, for example—but with asparagus I always like to keep it simple, with lemon and a sprinkling of tarragon.
First make the hollandaise sauce. Using a large balloon whisk, beat the egg yolks with a squeeze of lemon juice and salt and pepper to taste in a bowl set over a pan of simmering water. Beat vigorously for about 10 minutes until the mixture thickens. (To make sure the sauce doesn’t overheat, take it on and off the heat while you whisk, scraping around the sides of the bowl with a plastic spatula.) The aim is to achieve a golden, airy sauce that forms ribbons on the surface when the whisk is lifted.
Warm the olive oil in a small pan, then set aside. Off the heat, gradually add a little of the warmed olive oil at a time to the egg mixture, then return the pan over a gentle heat to cook a little more. Remove from the heat again and whisk in another dash of warm oil. Repeat until all the oil is incorporated and the sauce has a thick, mayonnaise-like consistency.
Whisk in lemon juice, salt and pepper to taste, plus 2–3 tablespoons of warm water to give the mixture a pouring consistency, then add the chopped tarragon.
Blanch the asparagus by plunging it into boiling salted water for 2–3 minutes until its rawness has been removed but it is still crunchy. Drain well and serve with the hollandaise.
HOW TO USE UP LEFTOVER CITRUS FRUIT
Cut the fruit into wedges and freeze until needed. They’re ideal for cooling drinks without watering them down as ice does, and also add flavor.