Above is a stock image of rose apples. Some describe them as bland, but they're not without a pleasant, distinctive flavor. They've got a nice crunchy texture, and there's no need to remove the skin or seeds.
If you know anything about Buddhism, you're probably aware that the Buddha's enlightenment came as he sat under a fig tree, the Bodhi tree, ficus religiosa. You're probably also aware that he practiced asceticism for seven years prior to enlightenment, and then determined that asceticism was futile in his quest.
What made him change his direction and accept food from the locals? As the story goes, a memory impinged on his ascetic practice. He recalled a time when, at the age of 9 years, he felt great peace and completeness. The young prince Siddhartha was sitting alone under a rose apple tree, away from nearby festivities and this profound feeling, a glimpse of the "first jnana" as Theravadans would say, washed over him. Recollection of this time was enough to set Siddhartha on the correct path, first questioning whether these feelings might lead him astray yet again, and then quickly developing a sense of certainty that he had seen the true way. At that point, he was 7 days away from enlightenment.
The rose apple story is a tad obscure. I wasn't aware of it until recently, and most casual Thai Buddhists aren't aware of it (noooooo....he sat under the fig tree!). But I find it quite powerful, more so than the fig tree story and the accompanying accounts of miracles. Many folks can relate to a feeling of completeness, perfection, freedom from expectations, whatever, that has spontaneously arisen in a natural setting. The rose apple story lets you know, if you didn't already know, that there's something incredibly profound and worthwhile in these moments. It's not illusory...far from it.
Except....it really wasn't a rose apple tree, as you'll hear in Western accounts of the event. It was a not-particularly-tasty sort of "black plum." The problem, not surprisingly, lies in the translation. "Chomphu", pronounced a certain way, refers to the rose apple. Change the tone a bit, though, and you're referring to a different sort of tree. It's "chomphu preuk" in formal Thai language, or "ton wa" more colloquially.
Of course, there's a chance that the Thais are actually wrong here. Probably not, though. Next time I meet a fluent Pali/Sanskrit Tripitaka scholar, I'll make a point of asking and will update the blog.