aha!! I grew this a few years ago when my mother in law gave me seeds for bitter melon and this came up instead!
When I asked my reliable sources (the old ladies in my neighborhood who have gardens) everyone remembered eating them as a kid in the country and nobody had seen one in years. I was happy to share them.
In my garden they are ripe just about at the time when my cucumbers
poop out, so I use them raw as cucumbers in salads, etc. I stir fried them a few times as well (if you search "crow's beak vegetable" you find that in Bhutan they're called this and often used this way-- in Vietnam, there is another plant with this same name and YMMV, but it looks like they are cooked the same way). They inevitably produce WAY more than I can eat/use/share, so the
rabbits get them. Rabbits love the vines/foliage, btw.
They are resistant to everything in my garden- especially the powdery mildew that kills the cukes.
(also they can be invasive. i think i pulled them out for a few years before they stopped coming back.)