How to Make It
Using a large citrus juicer, ream 12 of the pomegranate halves to yield 2 cups of juice. Strain the juice if necessary to remove any seeds or white pith.
In a small saucepan, combine the sugar with 1/2 cup plus 2 tablespoons water. Simmer the syrup over moderate heat until thick and reduced to 3/4 cup, about 5 minutes. Let cool to room temperature. Stir the syrup and lemon juice into the pomegranate juice. Transfer the mixture to an ice cream maker and freeze according to the manufacturer's instructions. While the sorbet is churning, chill a stainless steel bowl in the freezer. As soon as the sorbet is done, transfer it to the chilled bowl.
To serve, scoop the pomegranate sorbet into chilled dessert bowls or Champagne saucers. Pour Champagne around the sorbet, garnish with 3 or 4 Candied Clementines and sprinkle with the pomegranate seeds.