Heat 2 packages frozen raspberries, thawed, and 1 cup current jelly to boiling. Mix 2 tablespoons cornstarch and 1 tablespoon cold water; stir into raspberry mixture. Heat to boiling, stirring constantly. Boil and stir 1 minute.
Strain sauce; pour into dessert fondue pot and keep warm. Spear dippers and swirl in fondue.