Steeping: Get rid of as much as the white coating inside the peel. Mix the rum and the mandarin peels. Put in a jar and leave in the refrigerator for 5 days.
Straining: Strain the rum with a clean cloth, discard the peels and set the rum aside.
Mixing: Mix 1 cup of water and the sugar and boil over low heat until only a third of the liquid is left. Cool to room temperature. Mix the syrup with the rum.
Serving: Chill before serving.
Notes
Take into consideration that the preparation time does not include the 5 days for steeping.The color of the liqueur depends on what rum you use. I prefer dark rum, but you can use what you have at hand.Use white sugar if you want it lighter in color, brown if you want it darker.