Boil the potatoes in salted water for 20 minutes, then peel and cut into slices or cubes.
Roast the pine nuts without fat in a pan until golden brown. Pluck the basil, wash and shake dry and put in a blender. Add half of the pine nuts. Mash the garlic, grate the parmesan and add it too. Pour in the olive oil and mix everything together. Season to taste with salt, pepper and a squeeze of lemon juice. The pesto shouldn`t be too firm, otherwise the salad will be too dry. Possibly add a little more oil.
Halve the cherry tomatoes and add to the potatoes with the mozzarella balls. Add the remaining pine nuts. Mix with the pesto and season well again.
Roughly pluck the Parma ham and add to the salad.
A fresh ciabatta and a glass of Chianti go well with it.