Soak rolls in cold water. Peel onion and dice very finely. Chop anchovies very finely. Squeeze the bread roll. Knead the minced meat, egg, onion, bread roll, mustard, anchovies, 1 teaspoon salt and 1 teaspoon pepper in a mixing bowl with the dough hooks of the hand mixer. Form approx. 8 meatballs of the same size from the minced meat mixture
Bring 2 litres of water and 1 1/2 teaspoon salt to the boil in a wide saucepan. Bring the meatballs briefly to the boil in boiling salted water and let them simmer for about 12 minutes at low to medium heat.
In the meantime, peel and wash the potatoes, possibly halve them depending on their size and cook in boiling salted water for 20-25 minutes. Lift out the meatballs, drain and keep warm. Measure 650 ml of cooking water of the meatballs
Melt the fat in a saucepan, dust with flour, sauté and gradually deglaze with cooking water and cream while stirring. Bring to the boil, stir in capers and lemon juice, season to taste with salt, pepper and sugar. Heat the meatballs in the sauce briefly
Wash parsley, shake dry and chop finely, except for a few leaves for garnishing. Drain the potatoes, sprinkle with parsley, toss briefly with the lid closed. Arrange meatballs with sauce and parsley potatoes. Garnish with parsley leaves. Served with pickled beetroot