Prepare tortellini in boiling salted water according to package instructions, drain. In the meantime wash, clean and chop the tomatoes. Wash and clean spring onions and cut into thin rings.
Wash the basil, shake dry and cut the leaves of 3 stems into thin strips. Mix vinegar and pesto, fold in oil. Mix tortellini, tomatoes, olives, basil strips and pesto vinaigrette and season with salt and pepper.
Arrange salad and decorate with basil leaves.