This one was plucked from a tree at the finca by my nephew just before New Year. (The parasita on the right was one of many that cover the branches of the anonales up there.)
The pulpy flesh inside is thick and creamy, slightly lumpy or even gritty on the tongue, hence the English name, custard apple. At their best, the taste might be compared to that of an oddly lukewarm ice-cream.
It's rich in carbohydrates, potassium, phosphorous and calcium.
Supposedly first cultivated in the Yautepec river region (in modern Mexico) around 1000BC, the name anona comes from the Taíno word annon.
My Chilean friend tells me that down there they call them chirimoyas. (I've seen some sources which assert an Andean origin for the fruit. There are certainly many different varieties.)