The pulp they were excising was also a greenish yellow color, quite glossy, and with pronounced black round seeds.
I so wish I had taken a photo of the boys.
I asked the boys about they fruit they were working with and was told it was Maracuya. They also explained it was quite agria (sour).
They offered me one, which I gladly accepted.
After I got home with my new find I started researching. Apparently the Maracuya is the fruit of the Passion Flower vine! I love the passion flower, what a gorgeous flower!
Not knowing exactly what to do I scraped the pulp into my blender, added about a litre of water, several tablespoons of sugar, and processed until the seeds were quite fine. I tasted, adjusted sugar to my taste and then offered a glass for myself, my housekeeper, and husband.
The skin of the fruit is quite tough and very rigid, but the scraping of the innerds was quite easy.