Cover and bring a saucepan of water to the boil. Add beans and cook, uncovered, for 45 seconds. Drain and place them in a bowl of iced water. Meanwhile peel and cut the potatoes into 1cm cubes, then place them in another saucepan of salted boiling water for 2-3 minutes.
Cook the pasta in salted boiling water (according the packet directions) ensuring there is enough water to cover the pasta. Drain the pasta and sauté in a frying pan with potatoes, beans and the Saclà Pesto alla Genovese diluted with a small ladleful of the cooking water.
Serve topped with your favourite Grana Padano cheese and salt and pepper if required.