In a food processor fitted with the metal blade or in a blender, combine the raspberries and marmalade and puree until smooth. Strain the mixture through a fine-mesh sieve to remove the seeds. It is difficult to remove every seed, so don't worry if a few make their way into the sauce. Stir in the orange zest, the sugar and the orange liqueur, if suing. Store in a tightly covered container in the refrigerator for up to 5 days. - Updated: November 30, 2007
