Peel and wash the potatoes and cook them in boiling salted water for 20-25 minutes. In the meantime peel and finely dice the onions. Wash the dill, dab dry and chop finely. Chop the toast and crumble finely in a universal chopper.
Cut the fish into pieces and mash it. Mix fish, egg, half onions, toast, half dill and lemon juice well, season with salt and pepper. Form 28 mini meatballs from it. Heat 2-3 tablespoons of oil, fry the meatballs in portions at medium heat for 2-3 minutes, turning once.
Season vinegar with salt, pepper and sugar, stir in 2 tablespoons of oil drop by drop. Stir in the remaining onion. Clean and wash the salad. Wash basil and parsley and dab dry. Peel leaves and cut into strips.
Heat milk and butter in a small pot. Drain the potatoes, add the milk and butter mixture and mash everything with a potato masher. Mix with herbs, season with salt and nutmeg.
Arrange puree and meatballs on plates. Mix salad and vinaigrette and serve in bowls. Garnish with basil and dill.