In a skillet, toast the nuts over medium heat (without any use of oil or cooking sprays), stirring frequently (don’t let them burn!), until nice and fragrant, 3 to 5 minutes. Tip the toasted nuts into a clean bowl to cool for a few minutes.
Make the pesto:
Combine the basil, cooled nuts, parmesan, lemon juice, garlic, and salt in a food processor or blender. With the machine running, slowly drizzle in the olive oil. Continue processing until the mixture is well blended but still has some texture, pausing to scrape down the sides as necessary.