Looking at various recipes, it wasn’t hard deciding which ingredients to keep and which to drop; it was tweaking the amounts that gave me a bit of trouble. Eventually, I got it right to where I wanted it using 11 ingredients. Here’s a caveat though: some dishes are more of a matter of taste than others, and I think guacamole is up there at the top of the list. I may find my recipe just right, but you may think it needs more or less of this and that, or lacks a 12th and 13th ingredient, or uses some ingredients you shouldn’t have in guacamole. Still, if you do try this recipe or have your own, or even if you like your restaurant guacamole a certain way, I would love to hear your thoughts.
Edit September 16, 2012
Here's a 12th ingredient: one small Belgian endive. I have never seen it in guacamole but I figured its taste goes well with cilantro, and it really does. It makes this guacamole taste even better. You can also serve endives with the dip itself. If you look up endives + guacamole on Google, you'll see there are a few instances of that.