Combine 1/2 cup granulated sugar, 1/2 cup water and 4 rosemary sprigs in a small cream enameled saucepan. Set the saucepan over medium heat and stir slowly until the sugar dissolves completely and the liquid turns clear, about 2 minutes.

Bring the syrup to a gentle simmer, then pull the saucepan off the heat right away. Let the rosemary steep in the hot syrup for 15 minutes, until the kitchen smells distinctly of rosemary and the syrup has turned a pale gold.

Strain the syrup through a fine mesh sieve into a white ceramic bowl, pressing the spent rosemary with the back of a spoon to release the last of the oils. Discard the sprigs and let the syrup cool to room temperature, about 20 minutes.

Pour 1/4 cup granulated sugar onto a small plate. Run a lime wedge around the outside rim of each glass to dampen it, then turn the glass upside down and twist it gently in the sugar until the rim is coated in an even band.

Pour the cooled rosemary syrup, 4 cups cranberry juice and 1 cup orange juice into a large glass pitcher. Stir with a long wooden spoon until the liquid turns one even, deep ruby color with no streaks of syrup left at the bottom.

Cover the pitcher and refrigerate it for at least 1 hour, or up to 2 days, so the base is properly cold before any bubbles go near it.

Tuck the 2 remaining rosemary sprigs and the fresh cranberries into the chilled pitcher so they float near the top, visible through the glass.

Add 2 cups ice cubes to the pitcher no more than 20 minutes before guests arrive, so the drink stays cold without turning watery.

Pour in 3 cups cold sparkling water or ginger ale slowly, down the inside wall of the pitcher, right before you plan to serve. The surface should foam up gently and settle into a steady fizz across the top.

Pour immediately into the sugar rimmed glasses and serve right away, while each glass still shows a thin layer of bubbles climbing the side.