In a small saucepan over medium-low heat, heat cranberry sauce and rosemary. Let simmer for 10 minutes, stirring often.
Remove rosemary and transfer cranberry sauce to the bowl of a blender. Add maple syrup and purée mixture. Strain juice from solids using a fine-mesh sieve or colander. Discard solids.
In a small cocktail pitcher, pour sparkling wine and 2 tablespoons cranberry sauce mixture. Mix well. Strain cocktail through a sieve into 2 Champagne glasses.
Garnish with candied cranberries and serve.
Notes
- Candied cranberries: You can make these by simply tossing cranberries lightly in water and them in a bowl of granulated sugar.