When I was growing up in Southern California, avocados were so common we rarely had to buy them: neighbours and friends would give us sackfuls from their trees. We'd eat them as snacks, with just a sprinkling of salt, or mash them into guacamole, add chunks into seafood salads, and top hamburgers with slices of the fruit. Last week, I wanted to cook Mexican food for friends, so I went to the supermarket four days early to buy avocados - the ones in Hong Kong are so unripe they take several days to ripen (put them in a paper bag - their own gases will hasten the process). Then I discovered Great in Pacific Place sells huge, ripe Australian avocados, which means I can make Mexican food anytime I want, without having to plan days ahead. For the best guacamole, make a salsa first with fresh tomatoes, chillies, garlic, shallots, cilantro and salt. Let the flavours blend for at least an hour in the fridge, then toss a large spoonful or so into a mashed avocado. It's wonderful with chips, especially Frito's. Alternatively, toss raw, shelled shrimp with fresh lime juice, chilli powder or cayenne to taste, chopped cilantro, salt and pepper and marinate for about 15 minutes. Sear until cooked, then toss with sliced avocados, salt and fresh lime juice. This is good wrapped in a warm flour tortilla or as a salad, with mixed leaves. For a Mexican-style tortilla soup, make a rich chicken stock, then remove the meat from the bones and shred. Simmer the broth with garlic, sliced onion, dried chillies and dried oregano. Serve the broth with side dishes of raw onion, the shredded chicken, minced fresh chillies, sprigs of cilantro, chopped tomatoes, quartered limes, tortilla chips and slices of avocado, and let your guests flavour their bowls of broth as they wish.