Add all of the ingredients to the bowl of a food processor or blender.
Blend for 2-3 minutes on a slow speed until the herbs and nuts are finely minced and mixture is smooth.
Use immediately or store in the refrigerator.
Notes
This recipe makes 3/4 cup of pesto. If you prefer your pesto to be thinner, turn blender back on and slowly dribble in more oil until it reaches the desired consistency. Can't find walnuts? Try using pine nuts or pecans instead.