For the Café de Paris butter, rinse anchovies and pat dry. Peel and chop the shallots. Puree the butter, anchovies, shallots, capers, mustard, ketchup and cognac with a hand blender. Wash tarragon and shake dry.
Pluck off the leaves, chop very finely and stir in. Season to taste with Worcester sauce, salt and pepper. Cover half of the butter and chill for about 30 minutes. Freeze the rest.
For the steak, pat the meat dry and cut it into 4 pieces (approx. 3 cm high). Heat up the lard in a pan. Sauté the steaks in it for about 1 minute on each side. Season with salt and pepper.
Switch down to medium heat. Then continue to fry for 3-4 minutes on each side for one pink steak (medium). Wrap the finished steaks in aluminium foil and let them rest for about 5 minutes.
In the meantime, whip the cream until stiff. Set aside 2 tablespoons of whipped cream. Boil up the rest in a pot. Reduce heat. Whip the cold butter bit by bit. Fold the cream into the sauce.
Arrange the fillet steaks and pour the hot Café de Paris sauce over them. Serve with French fries and a green leaf salad.