Tamarillo by John Spottiswood.

This fruit is notable more for its ravishing beauty than its flavor. It's about the size of a oblong plum, with a smooth peel that can be purple, red, orange, or yellow, with the yellow variety tending to be a bit sweeter. Slicing it in half reveals black or orange flesh (the darker the peel, the darker the flesh) surrounding a nest of seeds. It's more acidic than sweet, and tastes a bit like a tomato. It's best if it's peeled and cooked before eating.