Start by clarifying the butter: place it in a saucepan over a low heat and allow to melt. The milk solids will separate from the fat in this process. Skim off any foam that comes to the surface and then pour the clear clarified butter into a container, leaving the milk solids in the pan.
To make the hollandaise sauce: peel and finely chop the shallot. Place in a saucepan with the white wine, vinegar, black peppercorns and thyme. Place the pan over a medium heat and reduce until you have approximately 3 tablespoons worth of liquid. Pass through a fine sieve to separate the liquid from the solids.
Place the egg yolks in a bowl, add the white wine reduction and season with salt. Place the bowl over a pan of simmering water and whisk vigorously until you have a fluffy sabayon. Cook until the mixture reaches the ribbon stage and then 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.
To cook the tenderstem broccoli: Bring a large saucepan of salted water to the boil and then add the peeled asparagus. Blanch for 2-4 minutes until the tenderstem are tender but still have a bit of crunch in the centre.
«If your mixture starts to split from being too cold, add a tablespoon of hot water and whisk to bring it back together again.»