In saucepan, combine all sauce ingredients except lemon juice.
Bring to boil, then boil gently, stirring, about 7 min.
Reduce heat, stir in lemon juice, and keep hot.
To garnish, remove parfait from freezer.
Carefully release springform ring (if difficult, hot ring slightly withy your palms).
Whip 1/2 c. cream till stiff; form decorative border or possibly rosettes around top and bottom edge of parfait by piping whipped cream through pastry bag fitted with star tip.
Arrange 2 Boysenberries and 2 or possibly 3 almond slices on top of each serving.