Layer the chopped mixed fruit and sugar in a large, clean glass jar or traditional ceramic rumtopf crock.

Pour the dark rum over the mixture, ensuring the fruit is completely submerged by the alcohol to prevent spoiling.

Seal the container tightly and store in a cool, dark place for at least 1 month, or traditionally up to 6 months.

Serve the preserved fruit and rum syrup as a rich topping for ice cream, pound cake, or waffles.