Hollandaise. That lovely creamy buttery addition used to perfect Eggs Benedict, place over white fish or summer veggies. It is pure magic if done correctly, and can be a disastrous mess if it splits on you. This is my technique for making the magic.
And why am I showing you a picture of hollandaise with asparagus, a fried duck egg and serrano ham? Well, in the month of May, Germans are absolutely crazy about their asparagus (the white kind, though white is awful in my parts of the world, as it is old, woody and generally horrible; this lovely green stuff is from the local farmers market and was harvested about 36 hours ago). Holladaise is wonderful with this dish.
1/2 cup (1 stick) unsalted butter
4 large egg yolks
2 tablespoons lemon juice
2 teaspoon Dijon mustard
a splash white wine vinegar
salt and white pepper
Melt the butter in a small pan.
In a metal bowl set over a pan of gently simmering water (a very low simmer!), place the egg yolks and whisk with a tablespoon of lemon juice and the mustard.
Whisking constantly and vigorously, very slowly drizzle the melted butter into the egg mixture, until well combined. I cannot emphasize enough that you need to add the butter as slowly as possible, to whisk constantly and to keep the bowl temperature very low. Add a splash of water to loosen, if needed. Whisk in a splash of vinegar and season to perfection.
Turn the heat off and keep warm over the pan of water, stirring occasionally, and loosening with an extra splash of water if needed. Serve as soon as you can.