For the dumplings: Mix all the ingredients for the dumplings well and steep in about 15 min. From the dumpling mixture with wet hands form dumplings with a diameter of in about 7 cm and make in slightly boiling hot salted water in about 10 min. For the sauce: clean, rinse and cut the leek into fine rings and sauté in light butter. Dust the sautéed leek with flour and pour in the beef broth. Season with salt and pepper, reduce liquid. Pluck parsley and chop finely. Stir the parsley into the leek.
Spread leek sauce evenly on plates, arrange two dumplings on each. Garnish with a halved cherry tomato and a little parsley.