Wash the potatoes and cook in salted water for about 20 minutes. Quench, peel and let cool. Clean and wash the vegetables. Cut celery into thin slices, tomatoes into eighths. Dice mortadella or meat sausage.
Peel and finely dice the garlic and onion. Season vinegar with salt, pepper and sugar and beat the oil into it. Stir in the garlic, onion and basil. Cut the potatoes into slices. Mix the prepared salad ingredients and fold in the marinade.
Cover and leave to soak for 1-2 hours. Season to taste again before serving.