To prepare the béarnaise sauce:

Pour the white vinegar in a pan. Add in the scallions, parsley and tarragon and stir constantly over low heat for about 10 minutes, until the liquid reduces approximately to 3 tablespoons.

In another pan, heat the butter over low flame until it is melted.

In a third pan, place the egg yolks and strain the scallions mixture over them through a fine sieve. Press with a spoon to extract as much liquid as possible. Discard the strained herbs. Flavor with salt and pepper.

Place the pan in a double boiler containing simmering water. Stir constantly the sauce until it begins to thicken, remove the pan and turn off the heat.

Slowly add in the melted butter and pinches of chopped tarragon. Stir well and pour the béarnaise sauce in a serving bowl

To prepare the chateaubriand steak:

Preheat the oven to 260C.

Place the garlic in a small bowl and sprinkle it with salt. Crush the garlic, add in the peppercorn and 1 tablespoon of oil.

Brush the veal filet with the garlic mixture and let it marinate for 30 minutes.

Heat the remaining oil in an ovenproof pan over medium flame. Cook the veal filet in the pan until both sides turn brown.

Transfer the pan to the oven and bake for about 10 minutes, until the meat is well done. If you like rare meat, bake for less time in the oven.

Remove from oven and place in large plate and cover with aluminum foil. Then allow t rest for 15 minutes.

To serve, place the veal filet on individual serving plates and pour over the béarnaise sauce.