My first custard apple appeared to me as a gift from a previous landlord during the Tet Holiday. It was initially repulsive - I encountered sickly sweet, mushy flesh clinging to ebony seeds. After a couple more tastes, it became instantly addictive. We are now firm believers (mang cau zealots) and devour a couple weekly. It's about the same size as an apple, but couldn't be more different. Originally from the tropics of the New World, they are now common throughout Southeast Asia as a feral species (like that amorous cat down the street that won't stop howling). The South Vietnamese variety (grown predominantly in Ninh Thuan and Ba Ria-Vung Tau Province) has a pale green, bulbous skin covered in diamond-shaped scales that tend to blacken as it ripens. You may also encounter small clumps of white pollen on the exterior - we first mistook this for mold and were grossed out.
Plucked from a semi-evergreen tree, transported to the market in thundering lorries, and placed before your hungry eyes - there is no dainty way to eat a custard apple. Wait until it's ripe and you can easily peel the scales off. Eat the flesh with a spoon, haughtily spitting out the hard black seeds as you come across them.
This is a wonderful dessert. Aptly named, the flesh is a true delicacy and is fantastic in a smoothie or neat. Word to the wise - enjoy with moderation, you may get a stomachache from over-indulgence in this decadent fruit.