Put the basil, garlic, salt and 2 or 3 grinds of pepper in a food processor and process until the basil and garlic are finely chopped, about 15 seconds. With the machine runing, pour 1/4 cup of the olive oil down the feed tube in a slow, steady stream, Turn off the processor and add the Parmigiano. Process until the cheese is incorporated, about 20 seconds. With the machine running, slowly add the remaining 1/4 cup oil. Add the nuts and pulse until they’re coarsely chopped.
Tip: You can make whole wheat (organic) pasta and add the pesto to it.