AVOCADO
Avocados are the creamy fat-rich vegetables (or actually fruits!) that are available throughout the year, although they are at their best during the warm seasons. Avocado stems from Central America, belongs to the laurel family, and contains low amount of sugar or starch. It does contain however a lot of fat, up to 30% - or 15% on average, although this fat is healthy and must not be confused with the unhealthy animal fat. Indeed, avocado fat is mostly monounsaturated, reminding very much of olive oil, and it is very good for promoting cardiovascular health. Avocado got its name from the old word "ahuacatl" which literally means "testicle" - for some reasons, the early civilizations saw resemblance between the one and the other.
Avocado has an interesting life physiology. It doesn't start to ripen until it's picked from the tree, and the ripening process takes about a week, and is proceeding best at temperatures slightly below or at room temperature. The ripening is triggered by a gas called ethylene, which is a universal ripening hormone of the fruits. If you want to speed up the ripening process, you can keep avocados in a bag of bananas (high ethylene producers) and let them influence the avocado's adulthood.
As mentioned above, the fat in avocado is good for your heart and blood vessels - an effect that is further augmented by potassium and folate. The avocado will also help to absorb the healthy carotenoids from other vegetables.
When buying avocados, choose the ones that are just slightly soft, as they will soften up even more within a day or two. You can also buy the hard ones and wait until they get soft. Make sure their skin is unblemished. Do not store them in a cold environment, which would inhibit the ripening process. However, you can store them in a refrigerator after they have ripened.
Prepare the avocados by cutting them in two halves, sliding the knife blade along the seed, then separating the two halves from around the seed and finally removing the seed (you can use a knife to stick it into the seed if necessary, but be careful as it is very slippery!). Then remove the flesh with a spoon.
Avocado is eaten raw and is often pureed, simply because it's an easy thing to do. The flesh of the avocado is very soft, thanks to all the unsaturated fat, and can be easily mashed. However, as soon as the flesh is exposed to the air oxygen it starts to turn brown (pretty much like artichokes or apples). The remedy is the same as for the other veggies - mix the avocado with some lemon juice, or/and wrap it tightly in a plastic wrap. If you want to cook avocado (not recommended) then remember that the heat will generate some disturbing bitter flavors in it, so if absolutely necessary - add the avocado to the dish at the very end of cooking and let it just heat through.
There are several different types of avocado, with various fat contents, colors, and shapes. The Guatemalan avocados have the least fibrous flesh and fairly small seeds. In USA, the most widely used avocado is the Hass avocado, which is Guatemalan and one of the best. However, there are some more flavorful variants, including Fuerte, Pikerton, Reed, and the less fat-rich variants like Bacon, Zutano, Booth, and Lula (the last two are from Florida).
Avocado goes well with: shellfish and smoked fish, and the classic additions to avocado purée include onions or shallots, chilli, lime, lemon, little sugar, tomatoes, and herbs like parsley or chives, or why not some cilantro? Avocado is good with many things.