I'm always excited to try exotic fruits, and even more excited when I find them available in the U.S. Last summer, when I went to Taiwan, I was introduced to a new fruit: cherimoya. I found the fruit very tasty and ate it almost everyday while I was in Taiwan, since I figured I wouldn't be able to taste it again for a long time. However, a few weeks ago while shopping at Ranch 99, I discovered that they now sell cherimoyas! At $3.69/lb, this heavy fruit isn't cheap, but I had to try it anyway.
The fruit resembles an unripe avocado with scales. They usually come in slightly odd shapes and are green with some brown spots. They tend to be pretty big and heavy. I don't know much about picking cherimoyas. I usually look for ones that are mostly green, unbruised, with an elongated shape.
The cherimoya should be hard when you buy it. Then, let it ripen naturally by storing it at room temperature (not in the fridge!). I usually leave mine on my kitchen counter. It takes about 3-4 days to ripen. You can poke it lightly to see the progression. When it is fully ripe, it will be soft to the touch all around and the skin will turn more dark green/brown.
The flesh inside should be super soft, like the consistency of baby food. I usually use a small spoon to scoop out and eat the flesh. There are some small black seeds which you can just pick out. A ripe cherimoya tastes very, very sweet. Probably one of the sweetest fruits I've ever eaten. I usually will only eat about half in one sitting. It tastes a bit like a very ripe d'anjou pear, but sweeter.