Empty the preserves into a heavy saucepan and heat over medium low for 3 to 4 minutes until they soften and melt.Add the cranberries and cinnamon; stirring constantly while mixture comes to a boil; cook until berries begin to pop. Reduce heat to low and simmer 15 to 20 minutes until the sauce is glossy and thick. Crush some of the berries against the side of the pot with your wooden spoon. Stir in the Truvia or Splenda to taste and cook 5 more minutes before removing from heat to cool.For a smooth sauce, place in blender and pass through a wire strainer using a rubber spatula.Transfer cooled mixture to a covered bowl and chill until ready to serve.