Beat yolks in the top of a double boiler until thick. Beat in heated maple syrup. Put over simmering water and cook, beating constantly until slightly thickened. Cool slightly, then refrigerate for at least 2 hours.
Beat whipping cream until it forms stiff peaks and fold into the cooled eggyolk/syrup mixture. In blender, puree half of the blueberries. Fold pureed berries into the cooled eggyolk/whipped cream mixture. Pour into a 1 to 1-1/2 qt. bowl or mold, or pour into individual cups or glasses. Freeze overnight. Before serving, garnish with remainder of berries, and a mint sprig.
Makes: 5 (1/2 cup) servings.
Date: March 19, 2003