- In a small pot, bring the water, vanilla pod and seeds, cinnamon and star anise to a boil. Strain into a 2-cup (500 ml) measuring cup. Add the ice cubes and let the water mixture cool. Cut the vanilla pod into 12 pieces. Compost the cinnamon stick and star anise.
- In a 12-cavity doughnut pan, divide the lime, ground cherries, cranberries and vanilla pod pieces among the cavities. Fill with the chilled water mixture. Add more water, as needed. Freeze for 6 hours (see note).
- In a punch bowl, combine all of the ingredients.
- In glasses with a wide opening (such as whisky glasses), place the rings of ice. Fill the glasses with punch.
The flavoured ice rings can be prepared in advance. To help unmould the ice rings, soak the base of the doughnut pan in hot water. Using a pointy, non-metallic utensil (such as a wooden skewer), press between the ice and the edge of the pan to pop the ice rings out. Store the ice rings in an airtight container in the freezer. This way, they will be ready to go when you serve the punch.
These ice rings are also great in a glass of juice or sparkling water.