Clarify the butter
Peel and finely chop the shallot. Place in a saucepan with the white wine, vinegar, black peppercorns and thyme. Place over a medium heat and reduce until you have approximately 3 tablespoons worth of liquid. Pass through a fine sieve, allow to cool
Place egg yolks in a bowl, add white wine reduction and season with salt. Place bowl over a pan of simmering water and whisk vigorously until you have a fluffy custard-like mixture. When it reaches the ribbon stage, remove from the heat and whisk in the clarified butter a little at a time. Check the seasoning and add a couple of drops of lemon juice to taste. Keep warm and serve with asparagus, egg's benedict or whatever takes your fancy. Alternatively, use a base for a bearnaise or mousseline sauce.
«If your mixture starts to split from being too cold, add a tablespoon of hot water and whisk to bring it back together again.»