- Briskly whisk the egg yolks with 1 Tbs. warm water in a metal bowl set over a pot of simmering but not boiling water until they begin to noticeably thicken. If the eggs appear to be curdling, take the bowl off the heat, but keep whisking. Keep going back and forth from the heat until the mixture is uniform in texture and much lighter in color.
- Adding the melted butter, a pat at a time, while whisking. After about a fourth of the butter is in there, you'll see a major change in the texture of the sauce. Add a teaspoon of water at that point and step up the addition of the butter a bit. Keep going till all the butter is incorporated.
- Whisk in the cayenne and lemon juice. Serve right away.