Hollandaise

Whisk three egg yolks with a tablespoon of water over a pan of barely simmering water until they thicken into a pale foam that holds a trail, about 60 to 65°C. Don't let the bowl touch the water or the yolks scramble. Take it off the heat and slowly whisk in 200 g of warm melted butter, leaving the milky solids behind. Season with lemon juice, salt and cayenne. If it gets too thick, add a few drops of warm water. Keep it warm in a thermos for up to an hour.