Preparation Whisk 3/4 cup plus 2 tablespoons sugar, eggs and yolks in medium stainless steel bowl to blend. Bring lemon juice and butter to boil in heavy small saucepan. Gradually whisk hot lemon mixture into egg mixture. {Step One} Set bowl over saucepan of simmering water (do not allow bottom of bowl to touch water). Stir until beginning to thicken and thermometer inserted into mixture registers 160—F, about 4 minutes. Transfer curd to small bowl. Press plastic wrap onto surface of curd; refrigerate until cold. Puree thawed boysenberries and 4 tablespoons sugar in blender. Strain into medium bowl to remove seeds; discard seeds. (Curd and puree can be made 1 day ahead. Cover puree; chill curd and puree.) Using electric mixer, beat cream in large bowl until soft peaks form. Transfer 3/4 cup whipped cream to small bowl and reserve. {Step Two} Fold 1 cup curd into whipped cream to make mousse; reserve remaining curd. Spoon mousse into pastry bag fitted with large plain tip. Spoon 1 tablespoon berry puree into bottom of each of 6 Champagne flutes or 6- to 8-ounce wineglasses. Pipe 3/4-inch-thick layer of mousse over puree and top with generous 1 tablespoon reserved curd. Repeat layering with mousse and curd. Top with reserved whipped cream. (Can be made 8 hours ahead. Cover and refrigerate.) Garnish with fresh boysenberries, if desired.
Preparation Whisk 3/4 cup plus 2 tablespoons sugar, eggs and yolks in medium stainless steel bowl to blend. Bring lemon juice and butter to boil in heavy small saucepan. Gradually whisk hot lemon mixture into egg mixture. {Step One} Set bowl over saucepan of simmering water (do not allow bottom of bowl to touch water). Stir until beginning to thicken and thermometer inserted into mixture registers 160—F, about 4 minutes. Transfer curd to small bowl. Press plastic wrap onto surface of curd; refrigerate until cold. Puree thawed boysenberries and 4 tablespoons sugar in blender. Strain into medium bowl to remove seeds; discard seeds. (Curd and puree can be made 1 day ahead. Cover puree; chill curd and puree.) Using electric mixer, beat cream in large bowl until soft peaks form. Transfer 3/4 cup whipped cream to small bowl and reserve. {Step Two} Fold 1 cup curd into whipped cream to make mousse; reserve remaining curd. Spoon mousse into pastry bag fitted with large plain tip. Spoon 1 tablespoon berry puree into bottom of each of 6 Champagne flutes or 6- to 8-ounce wineglasses. Pipe 3/4-inch-thick layer of mousse over puree and top with generous 1 tablespoon reserved curd. Repeat layering with mousse and curd. Top with reserved whipped cream. (Can be made 8 hours ahead. Cover and refrigerate.) Garnish with fresh boysenberries, if desired.