Cut carrots, leek and celery into julienne strips.
Mix onion cubes with thyme.
Peel potatoes, grate coarsely and mix with potato starch and season with salt, pepper and nutmeg.
Season meat on both sides with pepper, coat one side with mustard, first press on thyme onions, then press on flour and fry crust side in hot oil until golden brown. Turn and cook until the core is pink.
Sauté the vegetable strips in hot olive oil, season with salt and pepper, add the chives and saute until al dente.
Fry the potato mixture in hot olive oil until golden brown. Arrange the röstis in the center of plates, spread the vegetable julienne on top, halve the rump steak, place on top, garnish with cress and pour on the heated brown veal stock.