This is a delicious fruit.
It’s what the Colombians call a Lulo. And apparently the Peruvians and Ecuadorians call it a Naranjilla. You can only find it in the temperate climates of North Western South America.
It tastes a little similar to feijoa, but also has overtones of green apple. Most Colombians seem to consume their fruit via juice, and that’s the way we have experienced lulo. But we ask for our juice sin azucar (without sugar) so we get more of a fruity taste.
I had a lulo juice on the way home from my first Spanish class today. Also enjoyed one of the great features of fresh juice drinking here. They always make too much juice for the cup they give you. If you hang about to drink some they invariably top you back up.