What a special treat this exotic little fruit is! The star apple is a modest, fist-sized member of the sapodilla family that is usually green in color (at least in Vietnam) and has a milky white and semi-translucent center.
Profoundly popular in the Caribbean, there are a few areas in the Mekong Delta (e.g. Tien Giang Province) where the fruit is also found in abundance. Also, known as the milk fruit due to its low acid, lactose-sweet taste, the star apple moniker is derived from its appearance when cut width-wise (a prominent star-shaped pit is visible).
To enjoy, slice in half and remove the sugary flesh with a spoon or, simply, cut the fruit into apple-esque sections after slicing it vertically. Remove the skin and the cumbersome black seeds. Add to a green salad, plain yogurt, granola, or enjoy it as a decadent dessert. As it is somewhat difficult to find in the markets here, I wish you all happy hunting.