Print Recipe

ROSAMUND’S BEARNAISE SAUCE

Everyone winter, I usually serve our Longhorn beef with horseradish sauce, made with freshly grated horseradish from the garden. At this time of year, I like to accompany it with a Bearnaise sauce – the tarragon and chervil in it give a lovely taste of summer. You can’t make this sauce without fresh tarragon but you can miss out the chervil at a pinch – though it is so easy to grow from seed and so hard to come by in a supermarket that I always keep a pot outside the kitchen window.
These classic French sauces have a reputation for being a bit of a fiddle. This one really isn’t provided you have an electric whisk. I think it is best served warm but you can make it in advance. However, in my experience the classic way to keep it warm – in a bain marie – is a route to disaster: a degree or two too much heat and the whole thing will dissolve into a curdled mess. A vacuum flask is the answer to your prayers and much more reliable!
Servings: 4 people

Ingredients

  • 3 small shallots
  • A good bunch of fresh tarragon – you are going to need at least 3 tbsp of finely chopped leaves
  • 1 tsp roughly crushed peppercorns
  • 3 tbsp  tarragon vinegar (or use white wine vinegar and be generous with the tarragon)
  • 1 tbsp  cold water
  • 4 decent sized egg yolks
  • 250 g  good quality unsalted butter (I remain to be convinced that clarifying it, which is what good French chefs tell you to do, really improves either the taste or texture and it’s all extra effort).
  • A good bunch of chervil – or more tarragon
  • Salt and ground pepper

Instructions

  • Peel and finely (really finely!) chop the shallots.
  • Remove the leaves from the tarragon and chop them finely so that you have at least 3 heaped tbsp.
  • Put the shallots and chopped tarragon in small pan with the peppercorns, vinegar and water.
  • Reduce to half the volume (keep a watch – it only takes five minutes or so). 
  • Leave to cool and then put the contents of the pan in the top of a double boiler or a Pyrex bowl set over a saucepan of hot water – keep the base of the bowl clear of the water.
  • Meanwhile melt the butter in a small pan (with a spout for pouring if you have one). 
  • Add the egg yolks to the bain marie but get the whisk and the butter ready before you put the pan over the heat.
  • Put the pan on the heat and whisk hard for 10 minutes – or until the eggs are thick and creamy, taking care not to let the mixture get too hot. Take the pan off the heat but, keeping the bowl over the hot water and whisking constantly, very slowly add the warm butter (just a little splash at a time to begin with but speeding up to a thin, steady trickle). REMOVE THE BOWL FROM ABOVE THE HOT WATER.
  • Add salt and grinding of pepper and, if you are serving the sauce straight away, chop the chervil or extra tarragon (leaves only if tarragon) finely and add to the mixture. If you want to keep the sauce until later, put it in a warmed vacuum flask and add the chervil/extra tarragon just before serving.
    Order Longhorn Beef