PreparationMake crust: Preheat oven to 350°F. Blend first 4 ingredients in processor until nuts are coarsely chopped. Add melted butter and blend until moist crumbs form. Press nut mixture onto bottom (not sides) of 9-inch-diameter springform pan. Bake crust until golden, about 8 minutes. Freeze while preparing mousse. Make mousse: Whisk first 3 ingredients in medium metal bowl. Set bowl over saucepan of simmering water (do not allow bowl to touch water). Whisk until candy thermometer registers 170°F, about 4 minutes. Remove bowl from over water. Using electric mixer, beat yolk mixture until cool and thick, about 6 minutes. Beat in liqueur. Beat 2 cups cream and orange peel in bowl to stiff peaks. Fold in yolk mixture. Pour mousse into crust. Cover and freeze overnight. (Can be prepared 3 days ahead; keep frozen.) Cut around pan sides to loosen torte. Release pan sides. Transfer torte to platter. If desired, spoon lightly sweetened whipped cream into pastry bag fitted with medium star tip. Pipe rosettes of cream around top edge of torte; place orange triangles between rosettes. Garnish with whole pistachio nuts. Cut torte into wedges. Serve with Boysenberry Sauce.
PreparationMake crust: Preheat oven to 350°F. Blend first 4 ingredients in processor until nuts are coarsely chopped. Add melted butter and blend until moist crumbs form. Press nut mixture onto bottom (not sides) of 9-inch-diameter springform pan. Bake crust until golden, about 8 minutes. Freeze while preparing mousse. Make mousse: Whisk first 3 ingredients in medium metal bowl. Set bowl over saucepan of simmering water (do not allow bowl to touch water). Whisk until candy thermometer registers 170°F, about 4 minutes. Remove bowl from over water. Using electric mixer, beat yolk mixture until cool and thick, about 6 minutes. Beat in liqueur. Beat 2 cups cream and orange peel in bowl to stiff peaks. Fold in yolk mixture. Pour mousse into crust. Cover and freeze overnight. (Can be prepared 3 days ahead; keep frozen.) Cut around pan sides to loosen torte. Release pan sides. Transfer torte to platter. If desired, spoon lightly sweetened whipped cream into pastry bag fitted with medium star tip. Pipe rosettes of cream around top edge of torte; place orange triangles between rosettes. Garnish with whole pistachio nuts. Cut torte into wedges. Serve with Boysenberry Sauce.