In a small saucepan over medium heat, combine the pomegranate juice and sugar, and bring to a boil. Reduce the heat to a simmer, and cook until reduced by half, 10 to 15 minutes.
Meanwhile, remove the frozen dessert from the freezer and let soften for about 10 minutes. Transfer to a bowl; swirl in 2 tablespoons of the pomegranate syrup and seeds. Return to the freezer for 1 hour. Then serve the cake with the pomegranate syrup-swirled frozen dessert.