To prepare pesto, you will need basil, garlic, pine nuts, coarse salt, Parmigiano Reggiano, Pecorino, and extra virgin olive oil. The key to the pure, intense flavor of homemade pesto is using the best ingredients possible. Ligurians make pesto using the precious small-leafed Genoa DOP basil, which grows on balconies throughout Genoa’s narrow old streets. Any basil will work well, but choose the freshest you can find with blemish-free leaves. If you don’t have pine nuts, you can use walnuts or almonds instead. While Italian recipes often call for 24-month-aged Parmigiano and Pecorino Sardo, any of these cheeses can be used, but avoid those with additives or anti-caking agents, which will change the texture of the finished dish. It’s also important to use the best extra virgin olive oil you can reasonably get, because the amount is large and you will taste it. If you want to enjoy the taste of infused olive oil on bread, it would be great here.
Next, combine the potatoes, green beans, and pasta. Russet potatoes or any type of potato you use in baking will work. If you can, choose Ligurian cup pasta. The spiral shape locks in sauce, providing more flavor with every bite. However, any pasta shape that has nooks and crannies, such as casaricci or fusilli, will do the same.