I've seen all sorts of things added to guacamole (onions, tomatoes, cilantro, etc), but it's my firm belief that the perfect guacamole has but four ingredients: garlic, lime juice, salt, and the all-important avocado. This goes back to the first time my friend Kama made fresh guacamole before my eyes. The flesh of a perfectly ripe avocado, scooped into a bowl, the juice of a lime, a minced garlic clove, and plenty of salt (more than you'd think to add). Mashed together roughly with a fork and not pureed, so you still have the odd chunk of creamy avocado, it was easy to prepare, gorgeous to behold, and absolutely delicious with a big bowl of tortilla chips.
This is now my go-to recipe whenever I make guac (Thanks Kama!), and so long as the avocado is ripe it's pretty much impossible to screw up. Feel free to tinker with the amount of garlic, lime juice and salt -- as mentioned I feel it needs a bit more salt than might be your instinct to put in, but give it a try and see what you think. If you're serving with salty tortilla chips you may want to back off on the salt a bit. While I used to only make guac when I had chips on hand, now I use it for sandwich spread as well (I prefer it to mayonnaise).
Don't forget that avocadoes, once sliced into, go brown quickly so try not to leave the flesh too long before adding the lime juice, which will stop the browning. Also, if you're wrapping up the leftover guac, place a sheet of plastic wrap directly over the guacamole and store it in an air-tight container.
'Don't Mess With Perfection' Guacamole
1 ripe avocado
Juice of 1 lime
1 garlic clove, minced
Salt to taste
Scoop out the avocado flesh and put it in a bowl.
Add the lime juice, garlic clove and salt.
Mash with a fork. You don't want a puree, but a rough mash.
Taste, and add more salt if desired.
Makes approximately one cup of guacamole.