Wash the potatoes and cook for about 20 minutes. Then rinse cold and peel. In the meantime drain the mozzarella balls. Pluck large basil leaves and chop the rest of the basil. Wash, clean and halve the tomatoes.
Sprinkle the cut sides with vinegar, season with salt and pepper. Stick basil leaves and mozzarella balls with wooden skewers on the tomato halves. Fry potatoes in hot oil until crispy. Season with coarse salt, pepper and chopped basil and cut in half lengthwise. Put salami slices between 2 potato halves and pin them with small rosemary stalks or wooden skewers