This recipe can be doubled very easily. At Spago we use a sweet olive oil, not too sharp and overwhelming, from the Emilia-Romagna region of Italy. This can be brushed over pizzas and fish, and it turns a simple pasta into something special. In Italy, pesto is generally made with mortar and pestle, which probably accounts for the name, but it can also be done in a blender, so you will find both methods below.