Bring plenty of water with a little salt and oil to the boil.
In the meantime, wash the tomatoes, remove the pithy interior and cut into small cubes. Also dice the mozzarella. Wash the basil briefly and cut the leaves into strips.
Cook the spaghetti al dente, drain and mix with the prepared ingredients. Season with freshly ground pepper and possibly a little salt (if you like, you can add a little olive oil over the pasta). Serve hot.
All in all, it tastes wonderfully fresh and is prepared in no time at all.