To make this pesto, all you need is a bunch of arugula, some excellent extra virgin olive oil (even better if delicately peppery, to match arugula’s bite), walnuts, and grated Parmigiano Reggiano. As you can see, this is a very short list of ingredients, but make sure to choose good quality ones. Read the recipe through before you make it. While you can blend the olive oil, walnuts, and arugula together in a food processor, make sure not to add the grated Parmigiano Reggiano until afterward, when you’ve already scraped your pesto into a bowl. This is to avoid overheating the cheese, which would change the pesto’s texture and flavor. Before adding the salt, taste: First, you’ll get the pure fresh, bitter, peppery taste of arugula, then the saltiness given by the grated Parmigiano Reggiano. You’ll be able to add just the right amount of salt to match your taste. …