Put the parsley on a cutting board and with a mezzaluna or sharp knife, finely chop. Put the parsley in a jar and add the freshly squeezed lemon juice. Add the salt, and black pepper, to taste, Parmigiano cheese, and extra-virgin olive oil. Mix well.
Pesto can be served fresh or it can be preserved in the refrigerator or freezer in an air-tight container. If freezing, omit the cheese and drizzle the top with oil. Thaw, then stir in the cheese.