Wash, clean and peel the cucumber. Radishes clean and wash. Slice both into thin slices. Whisk lemon juice with salt, pepper and sugar. Beat the oil in a thin stream. Mix the vinaigrette with the salad, set aside
Wash the fillet, dab dry and cut into thin slices. Put the starch in a deep plate and turn the fillet slices in it. Heat clarified butter in a large pan. Fry the meat in it in 2 portions, turning it for about 2 minutes on each side. Season meat with salt and pepper and remove. Deglaze frying fat with cream and 200 ml water, let it boil down a little bit. Add meat and season to taste
Wash herbs, shake dry. Pluck and chop the chervil leaves. Cut chives into small rolls. Mix chives into the salad and season again. Sprinkle chervil over the meat. Serve meat with salad. Serve with baguette bread (ask the baker for lactose-free variety)