Béarnaise can be a bit of a fiddle and it has a very irritating habit of splitting but it is well worth the effort. There is nothing more sublime than a fantastic grilled steak, crisp frites and béarnaise sauce, it is heaven on a plate.
• 1 small onion, chopped finely
• 2 cloves garlic, chopped finely
• 1 tsp dried tarragon
• 1 tsp whole peppercorns
• 2 tbsp white wine vinegar
• 2 tbsp water
• 2 egg yolks
• 1 tsp Dijon mustard
• 150g butter
In a small saucepan combine the chopped small onion, chopped garlic, dried tarragon and some whole peppercorns. Add 2 tbsp of white wine vinegar and 2 tbsp of water. Bring to simmer and reduce until you are left with about 1 tbsp of liquid, drain and put to one side.
Place a glass bowl (not a metal one) over a saucepan of just barely simmering water. The heat here is crucial for even just a shade too hot and the sauce will separate. Put two egg yolks in the bowl, add the reduced vinegar mixture, 1 tsp Dijon mustard, some chopped fresh tarragon (optional) and whisk. Slowly add a little cube at a time of room temperature/soft butter, whisking all the time, until you have added 150g of the stuff.
If the sauce does separate in another clean glass bowl put an egg yolk and slowly whisk in the separated sauce. It’ll be fine again so don’t worry!