Frozen Boysenberry and White Chocolate Parfait

Preparation

1. For Parfait:

   Step 1

   Line 9x5-inch loaf pan with plastic wrap. Puree berries and 1/4 cup sugar in blender until just smooth. Strain. Measure 1 1/3 cups puree and place in heavy small saucepan. (Reserve any remaining puree for sauce.) Simmer 1 1/3 cups puree over medium heat until reduced to scant 1 cup, stirring occasionally, about 8 minutes. Transfer to bowl and chill 30 minutes. Stir in cassis and lemon juice. Refrigerate reduced puree until ready to use.

   Step 2

   Combine 3/4 cup sugar, water and yolks in medium metal bowl. Set bowl over saucepan of simmering water. Using hand-held electric mixer, beat yolk mixture until it registers 140°F on candy thermometer, occasionally scraping down sides of bowl, about 5 minutes. Continue cooking 3 minutes, beating constantly. Remove from over water. Add warm melted chocolate and vanilla extract and beat until cool. Beat whipping cream in another large bowl to stiff peaks. Gently mix 1/4 of whipped cream into chocolate mixture. Fold in remaining whipped cream.

   Step 3

   Transfer 1 1/3 cups chocolate mixture to medium bowl. Fold in reduced berry puree. Fill prepared loaf pa n with 1/3 of remaining chocolate mixture. Cover with berry-chocolate mixture. Top with remaining chocolate mixture. Smooth top. Freeze parfait overnight. (Can be prepared 2 days ahead.)

2. For Sauce:

   Step 4

   Puree frozen boysenberries, sugar and crème de cassis in blender or processor until smooth. Strain. Add any berry puree reserved from parfait.

3. Step 5

   Unmold frozen parfait. Peel off plastic wrap. Slice into 1/2-inch-thick slices. Drizzle with sauce. Garnish with berries and fresh mint sprigs.