1. Finely chop 1/4 of a white onion, a big handful of cilantro, 1/2 of a seeded jalapeno (if you like) and one stalk of celery, leaves and all.
2. Scoop out the flesh of 3 avocados, and mash everything together in a bowl or with a mortar and pestle. Add plenty of kosher salt (tasting along the way) and juice of one lime (if it's small) and 1/2 a lime (if it's big).
3. Top with a little more chopped cilantro and maybe some red pepper flakes.