For Ligurian pasta, put the water to boil, salt it and put the pasta in it. In the meantime, peel the potato and then cut it into 3 mm thick slices, clean the green beans and cut them into 1 cm thick slices.
After half the cooking time of the pasta, add the potato and the beans to the pasta and cook until the pasta is al dente (about 5 minutes).
Drain the water generously and stir in the pesto and serve immediately