Place all ingredients, except avocado, in blender in order listed.
Cut avocado in half and remove pit. Scoop out flesh and add to blender.
Blend on medium speed until creamy but not smooth; it should have some texture. Mixture will be very thick; you may need to stop the blender a few times to scrape the pesto from the sides of the blender jar.
Notes
1. To soak pumpkin seeds, place seeds and 1 cup of water in a container and place in refrigerator for 6 to 24 hours. Drain well before using.2. This pesto is best eaten fresh as it will darken slightly in color upon storage. If you need to make it ahead of time, place in a container, press plastic wrap directly on top of pesto, and store in the refrigerator and it will be fine.3. Will keep for about 4 days in the refrigerator.