Recipe: Chicken with Tarragon by Raymond Oliver

From Raymond Oliver's 1967 cookbook. This recipe is quite simple to make and delicious, don't hesitate to use a generous amount of fresh chopped tarragon at the end of the recipe, that's the whole secret ; -)
Cut the chicken into pieces and quickly sauté them in a casserole in a little oil (for me: olive, otherwise rapeseed or sunflower) and a good piece of butter.
Remove the chicken once well browned. Drain it and flame with 1 liqueur glass of Cognac (Armagnac works very well too)
In the same casserole, add the freshly chopped shallots (125 g for a 1.5 kg chicken) with a knob of fresh butter. Let them brown well.
Return the chicken, pour in a good glass of dry white wine, and two nice branches of tarragon, salt, pepper.
Cover, let simmer for 25 minutes.
Place the chicken on a plate (preferably warm).
In the casserole, remove the tarragon branches, mix two deciliters of heavy cream with an egg yolk and heat without allowing to boil (very important).
Once the creamy consistency is achieved, pour everything over the chicken and sprinkle with chopped tarragon and chervil.
For me, just plenty of fresh chopped tarragon works fine, and I prefer to mix it with the sauce in the casserole just before pouring it over the chicken so the flavor is a bit more pronounced. Remember to keep some fresh chopped tarragon for decorating the serving dish.