Clean and wash the salad and drain well in a sieve. Clean the potatoes thoroughly and boil them in salted water for about 20 minutes. Drain the gherkins (collect the cucumber water) and cut into slices.
Dab the fillet of beef dry and cut into thin strips. Heat 2 tablespoons of oil in a pan and fry the fillet strips in portions. Season the meat with salt and pepper. Dust the meat with flour, sweat it on and add stock while stirring.
Let simmer for about 10 minutes. Peel onion and cut into thin rings. Cut beetroot into slices. Add 2 tablespoons cucumber water, cream and mustard to the sauce and season with salt and pepper.
Wash the thyme, dab dry and remove the leaves from 3 stems and chop coarsely. Drain the potatoes, rinse briefly and peel. Wash parsley, dab dry and chop the leaves finely.
Melt the butter. Toss potatoes in it and sprinkle with parsley. Add meat to the sauce, bring to the boil briefly and remove from the heat. For the vinaigrette, mix vinegar and 1 pinch of mustard. Stir in 3 tablespoons of oil and season with salt, pepper and a little sugar.
Mix salad, onion rings and beetroot and serve the vinaigrette extra. Arrange potatoes and meat and garnish with thyme and pink pepper berries.