1. Put cherries and cinnamon stick into a 1-qt. sealable glass container, such as a mason jar.
2. Bring sugar, brandy, and 1 cup water to a boil in a small saucepan and boil until sugar has dissolved.
3. Pour hot liquid over cherries and let cool to room temperature, about 2 hours.
4. Seal jar and chill until cherries have shrunk and absorbed liquid and are flavorful, at least 1 month and up to 4 months.