Wash the potatoes thoroughly and cook them in boiling salted water for about 20 minutes, drain, rinse and peel. Cut potatoes into slices. Peel onion and chop finely.
Knead minced meat, egg, onions, mustard, salt, pepper and paprika. Form 4 flat steaks from the minced dough. Heat 2 tablespoons of oil in a frying pan and fry the steaks in it at medium heat on each side for about 4 minutes.
In the meantime, dice the bacon. Clean and wash spring onions and cut into rings. Leave the bacon out in a dry pan. Add remaining oil, deglaze with vinegar and 75 ml water and simmer for about 1 minute.
Then season to taste with salt, pepper and sugar. Add spring onions. Pour vinaigrette over the potato slices and mix well. Arrange potato salad, minced steaks and herb butter on a plate and serve garnished with parsley, tomatoes and tomato cubes as desired.