Finely chop the red onion, coriander, tomatoes (optional), chillies, and garlic, and mix together in a large bowl.

Halve, de-stone, scoop out and finely chop the avocados and add to the mixture (do this last as avocados can brown quickly if left out).

For a truly authentic guacamole Mexicans use a special mortar and pestle made from porous volcanic rock called a molcajete along with local herbs. Assuming you don’t have those, the secret to a good guacamole is 1. not to over-mash or worse - blend - the mixture, and 2. use lots of fresh lime juice. It should be enough to simply chop your ingredients finely and mix together well with a fork.

Some people like to add a little extra virgin oil to the mix, but the crucial finishing garnish is lots of fresh lime and freshly chopped coriander. Any “guacamole” without these is a fraud.

Serve with plenty of corn chips as a dip. Also goes very well with tacos, enchiladas, nachos, tortilla wraps, and other Mexican dishes. Possibly a bit heretical, but some people also love the combination of hummous and guacamole in a “Middle East meets Mexico” decadent sandwich.