In a video posted by Food Network, Alton Brown says that guacamole should be chunky, so use a potato masher to achieve the desired texture. Then, the famous chef adds salt, cumin, and cayenne to the avocado chunks, potato-mashes the mixture, and stirs in chopped onion, Roma tomato, cilantro or parsley, seeded jalapeño, finely minced garlic, and lime juice.