Famed for exquisite gelato, Giapo Grazioli also proves a dab hand with pesto. He shares this recipe for spaghetti maria grazia, a zucchini and basil spaghetti dish he often makes when friends come for dinner. This dish is an adaptation from a famous seaside town in Italy's south. It's essentially a pesto made of fried zucchini, three kinds of cheese and fresh basil. But there's a twist. The secret to making it taste so good? Butter!