Look at what my colleague gave me today! It's buah kedondong ("Ambarella") (called "sar lei" in Cantonese) and it's grown in his garden. (Can I therefore assume it's pesticides free?). However those sold in the markets are larger size than these.
It can be eaten raw as it is, but of course after you have scrapped away those tiny brown spots. It has a crunchy texture and some of them can be awfully sour and these are best eaten when dipped in black soy sauce mixed with a little sugar and vinegar (optional), some chopped onions (optional) and chilies.However, if it's left to ripen to a little bit more until it's yellowish in color, it would taste sweeter.
You can even blend the buah kedondong into juice and then served it in a tall glass with ice and with one or two preserved plums ("kat chai") thrown into it to give it that sweet sour taste which is so refreshing after a heavy meal.