Adapted from Appetite by Nigel Slater
If you're not familiar with Nigel Slater, you should be. Now that his newest book The Kitchen Diaries:A Year in the Kitchen With Nigel Slater has received such good press here, more and more people on this side of the pond are finding out about him. The book that this recipe comes from is a one-of-a-kind book. It's about how to satisfy your cravings without slavishly following recipes. It is indeed about satisfying your own appetite. It's a wonderful book to have even if you have to order it from Amazon.uk.
This sauce, which is season-appropriate now as spring asparagus is crying out for it, is truly glorious even if it does seem like the scariest one to make. The real key is to heat it gently while constantly whisking and not letting it get too hot. This might sound like a contradiction, but you'll see, it's not. You will need a round-bottomed, heatproof bowl (I use stainless steel) and a saucepan for it to sit snugly on, as well as a plump balloon whisk. Approach this task with infinite patience and an absence of trepidation. Remember, this is supposed to be fun. And it is true that the proof of the pudding is in the eating. You will be well rewarded once you have mastered this sauce.
3 extra-large eggs (I don't really have to tell you free-range, do I?)
1 cup butter (This really IS 2 sticks. Don't get crazy, and don't tell Dr. Mehmet Oz. Get over it. As Nigel Slater says "We are talking heaven here.")
Half a lemon (maybe a little less if it's really juicy)
Separate eggs yolks from whites. Put the the yolks into a heatproof bowl. You can use a metal bowl or glass bowl. I usually use metal because it's light, and I can lift it on and off the saucepan to regulate the heat. (Refrigerate the whiles if you have another recipe you will use them for, but I hope it's not an egg white omelet, which, in my opinion, would not be an omelet at all.)
Fill a saucepan with water halfway up, and put it over a moderate heat. Sit the bowl with the yolks in it snugly on top of the saucepan, making sure it doesn't touch the water, then add a small splash of water to the eggs, and stir gently for a few seconds.
Cut the butter into twelve pieces. Add four pieces of butter to the egg yolks, and whisk firmly but slowly until the egg yolks have taken up all the butter. Slowly whisk in the rest of the butter. You will need slightly less than the two whole sticks.
Still whisking, squeeze in the lemon juice. The color should be a lovely light yellow. Add a little salt. Remove the saucepan from the heat.
The sauce will keep warm over the water for half an hour or so, but whisk it occasionally. This is the point at which it may curdle. No one is immune. But as Nigel Slater says, "It is worth the sweat."
If the sauce does break, throwing an ice cube in and whisking like crazy will work nine out of ten times.