This delicious mixture may be kept in a covered jar in the refrigerator for several weeks.
Cut off the stem ends of tamarillos and halve them lengthwise. Line a baking dish or roasting pan with baking paper or a Teflon liner. Sprinkle it with brown, raw or white sugar, allowing about 1/2 cup sugar to 500g tamarillos. Sprinkle the sugar with cinnamon, ground cloves and/or mixed spice to taste.
Place the tamarillos, cut side down, on the sugar and bake uncovered at 150 °C for about 30 minutes, or until the skins rise up and can be pinched and lifted away from the cooked fruit.
Spoon the fruit and syrup into a jar, and add about 3 Tbsp dark rum or brandy to the warm but not hot fruit. Cover and refrigerate. Stir mixture occasionally.
Spoon the tamarillo mixture over good quality vanilla ice-cream in small bowls or glasses.