In a blender or food processor, combine all ingredients. Pulse the blender about 15-20 times, scraping down the sides if needed, just until the hemp seeds taken on a slightly powdery texture and are well-combined with the nutritional yeast.
Leftovers keep for at least a week in an airtight container in the refrigerator.
Notes
No blender or food processor? Because hemp seeds are already so granular, you can easily make this recipe by grinding them slightly smaller (possibly in batches) in a spice grinder or coffee grinder. If you have neither of those implements either, you can toss the hemp seeds with a very light coating of oil, and then stir in the nutritional yeast and salt (the oil helps everything stick together). The texture won't be as buttery but you can still get the flavor this way.Yes, this hemp parmesan does take on a very slightly green color from the hemp seeds. This is normal.