Remove the basil leaves from the stalks. Rinse them under running water.
Add all ingredients together in a blender. (The best and most authentic way is with the pounder. Start with the leaves and add the other ingredients bit by bit.)
Note that the blades of the blender can produce heat which can change the color and taste of the pesto. So mix short and on a lower speed.
Seazon with salt and pepper.
You can keep this pesto in a sealed pot in your refrigerator for 2-3 weeks.