The basic ingredients in guacamole are ripe Haas avocados, onion, salt and freshly-squeezed lime juice. Common additions include cilantro, tomato, and jalapeño, serrano or poblano peppers.
Guacamole is a composite of two Aztec words meaning avocado and mixture. In Mexico, guacamole is a category of food, rather than a particular dish. Blends of avocado with any compatible foods, authentic guacamoles can contain pork skins, tomatillos or cucumbers.
Avocados are fats, and cold fats do not stimulate the taste buds. Letting avocados become soft to the touch and keeping them at room temperature ensures peak flavor. Mashing salt, onions and optionally cilantro in a mortar or on a cutting board creates a paste that can be refrigerated until needed. Right before serving is the time to add peeled avocado with a squeeze of lime to the paste, using just enough lime to stabilize the avocado without overwhelming its flavor. Mashing the avocado to a chunky texture produces a traditional guacamole. Using a food processor to chop all ingredients, including the avocado, provides a guacamole with a smoother consistency.
One consideration when adding extra ingredients to the guacamole is avoiding any foods with high liquid content to prevent watering down the finished mixture. Another is to avoid foods with strong flavors that might mask the underlying taste.