Sugar apples on display in a market.
This lumpy fruit is about the size of a large apple, but there the comparison more or less ends. The skin is dusky green and covered in bumps the size of your fingertips. Most guide books to Thailand label this fruit as a custard apple, but in fact the custard apple is a different, though related, fruit.
Beneath the skin is a milky white flesh that many compare to custard, hence the confusion of names. Oddly enough, although I've always seen custard apples for sale in the markets, I've never encountered them in the fruit carts. It is probably because the fruit cannot be cut or easily segmented like the other firm fleshed fruits.
Like the pineapple, the sugar apple originated in the Americas and was bought to Asia by the Spanish and Portuguese.