Asparagus hollandaise

Serves four, as served at Le Caprice

Allow 250g asparagus per person and cook it as per the recipe for boiled duck's egg and asparagus soldiers.

For the hollandaise
40ml white wine vinegar
40ml water
1 small shallot, chopped
a few sprigs tarragon
1 bay leaf
5 peppercorns
3 small egg yolks
200g unsalted butter
salt and freshly ground white pepper

Place the vinegar, water, shallot, herbs and peppercorns in a pan and simmer to reduce until there is enough to fill a dessert spoon. Strain through a sieve and leave to cool. Melt the butter and simmer for five minutes. Remove from heat, leave to cool a little, then pour off the pure butter where it has separated from the whey. Put the egg yolks into a small bowl with half of the vinegar reduction and whisk over a pan of simmering water until the mixture begins to thicken. Slowly trickle in the butter, whisking continuously. If the butter is added too quickly the sauce will separate. When you have added two-thirds of the butter, taste the sauce and add a little more, or all, of the remaining vinegar reduction. Then add the rest of the butter. The sauce should not be too vinegary, but the vinegar should just cut the oiliness. Season with salt and pepper, cover with clingfilm and leave in a warm place until needed. The sauce can be reheated over a bowl of hot water and lightly whisked again. Either spoon the sauce over the tips of just-cooked asparagus, or serve in small bowls. Eat with your fingers; it tastes much better.