Peel and finely chop the onion. Melt 1 tbsp. butter in a pan and fry the onion cubes briefly until translucent. Knead minced meat, diced onion, egg and breadcrumbs and mustard to a mass. Season with salt and pepper. Form approx. 30 dumplings from the minced mass
Bring the stock, peppercorns, bay leaf and lemon juice to the boil in a wide pot. Add the meatballs to the stock, bring to the boil briefly, cover and cook over a low heat for about 15 minutes
Peel, wash and halve the potatoes and cook in boiling salted water for about 20 minutes. Remove the finished dumplings from the stock with a skimmer. Pour stock through a sieve and collect. Measure 500 ml stock
For the sauce, melt 30 g butter. Add flour and sweat for about 1 minute while stirring. Pour stock into the roux while stirring and bring to the boil. Simmer for about 5 minutes and season with salt and pepper. Refine with cream. Add meatballs to the sauce and heat up. Wash parsley, shake dry, pluck leaves from the stalks and chop finely. Drain the potatoes. Arrange potatoes and dumplings in plates and sprinkle with parsley