Put the Castillo de Canena oak smoke oil on the meat, not in the pan. Roast the meat in the pan on all sides until it is seared on the outside and juicy on the inside. Add the salt.
Melt in a casserole the mixture of butter and oil with Castillo de Canena oak smoke over low heat without boiling, and once melted, set aside.
In another casserole we poach for two minutes the very small chopped onion (brunoise) and the vinegar, add the water and the lemon, the egg yolks and a pinch of cornstarch.
Stir with a wooden spoon and place this mixture in a bain-marie. To do this, we put it in another pan with water and put it on the heat so that the pan with the yolks is hot but not on direct heat.
When the sauce is thickening, remove it from the bain-marie and add little by little the mixture of liquid butter and oil to the oak smoke, stirring constantly as if it were a mayonnaise.
Once all the smoked butter and oil mixture has been added and the sauce is thickened, add the parsley, salt and tarragon.