Hollandaise sauce (Sauce hollandaise)

1. Melt the butter over low heat and cool it to lukewarm (you can leave behind the white, milky sediment – clarified butter).

2. In a heatproof bowl, whisk the egg yolks smooth with a tablespoon of water and the lemon juice.

3. Set the bowl over steam (above simmering water, not in it) and whisk constantly until it thickens to a creamy, pale cream.

4. Off the heat, drizzle in the melted butter in a thin stream, whisking constantly, until you have a thick, glossy emulsion.

5. Season with salt and pepper and freshen with a little more lemon juice as needed.

6. Serve lukewarm and at once (e.g. with poached eggs, asparagus, fish).

Tip: Hollandaise is a delicate emulsion – don't let the egg get too hot or it will curdle. Whisk patiently over steam and add the butter slowly; if too thick, a drop of lukewarm water rescues it.