The tamarillo, or tree tomato, is the smooth, glossy, egg-shaped fruit of a small fast-growing Andean tree in the nightshade family (Solanum betaceum). Its taut skin ripens to red, orange or yellow, and the tangy flesh — somewhere between a tomato and a passion fruit — is studded with edible seeds. Too bitter to eat with the skin on, it is peeled or scooped from the half, and the sweet-tart pulp goes into chutneys, sauces, juices and fresh dishes.