Asparagus and fava beans are both harbingers of spring, and that's the time to make this quick and easy pasta dish. The wide, flat shape of tagliatelle is ideal for cradlind the asparagus and beans, but you could also use linguine or papardelle (or even spaghetti). If you can't find baby broad beans, you can use more mature varieties instead; these will require blanching and peeling before using, so enlist your family and friends to help out.