Chicken cooked with tarragon is lovely, this is just a little more sophisticated. Rarely mentioned these days, the hot emulsified sauces that nouvelle cuisine made stars of are really heavenly stuff. Their dependence on butter hasn’t helped their image in recent fat conscious years but I’m all for a great burst of luxurious flavour in small doses. Béarnaise is fabulous with chicken, steak, or thick white fish such as turbot.

This recipe will generate about a half a pint of béarnaise and is a rather generous quantity for four people, but it can be used from cold to enrich soup, or you could reheat gently in a baine marie but the chances of it separating are high. My advice is to let your belt out a notch for the day and nibble on dry crackers and salad tomorrow.

Ingredients - serves 4

1.8kg chicken
butter
salt & pepper

the sauce béarnaise:
180g butter
3 tbsp white wine vinegar
3 tbsp dry white wine
1 tsp coarsely ground black pepper
2 shallots, finely chopped
3 egg yolks
1 tbsp roughly chopped tarragon
salt to taste
to finish:
2 tbsp finely chopped tarragon or chervil
a squeeze of lemon juice

Method

Pre heat the oven to 200°C
Split the chicken along the backbone with a large kitchen knife, then push down on the breast bone with both hands to flatten the bird. Sit over a rack in a roasting tray, brush with melted butter, season and roast for 20 minutes then lower then baste and lower the heat to 180°C and continue for a further 40-50 minutes or until cooked and golden. Rest for a few minutes before jointing.

20 minutes before the end of cooking time set your new potatoes to boil in salted water and prepare the sauce. First melt the butter in a small saucepan, skim any scum from the surface and leave to stand. Place the crushed peppercorns, roughly chopped tarragon, wine and vinegar in a small saucepan and boil to reduce to a third of its volume. Allow to cool for a few minutes before whisking in the egg yolks to light. Over a very low heat (or in a bowl over simmering water), whisk gently but constantly until the mixture thickens and becomes creamy. Remove from the heat and whisk in the tepid butter - a few drops at a time to begin with and then faster as the sauce emulsifies. Don’t use the milky sediment of the butter.

When all butter is incorporated, finish with a little lemon and the finely chopped herbs and check seasoning. Serve whilst still warm over a joint of chicken and new potatoes.