Scatter 2 cups cranberries and rosemary sprigs in a bundt cake pan and fill halfway with water. Transfer to the freeze and let freeze overnight.
Place all ingredients for the simple syrup into a medium saucepan and bring to a simmer over medium heat. Stir until the sugar is dissolved and remove from heat. Cover and let steep for at least 30 minutes. Strain before using. This syrup can be made up to 3 days ahead of time.
Pour cranberry simple syrup, orange juice, vodka, and sparkling water into a punch bowl. Run bundt cake under warm water until the ice ring has broken free from the bundt cake. Transfer to punch bowl, add a few orange slices, and serve.