Meanwhile, add enough water to reserved juice to measure 1 1/4 cups. In 1 1/2-quart saucepan, mix 1/4 cup sugar and the cornstarch. Stir in juice mixture and raspberries. Heat to boiling over medium heat, stirring frequently. Boil and stir 1 minute; cool. Strain sauce through a strainer to remove seeds. Serve torte with sauce.