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FROZEN WHITE CHOCOLATE MOUSSE CAKE

FOR THE CRUST:
1 cup vanilla wafer crumbs
3 tablespoons unsalted butter, melted
FOR THE MOUSSE:
6 ounces white chocolate, chopped
1 cup sugar, divided use
1/4 cup water
4 large egg whites
1 pinch cream of tartar
1 1/2 cups chilled whipping cream
3 tablespoons Grand Marnier, divided use
1 teaspoon vanilla
2 ounces chopped white chocolate
FOR THE RASPBERRY SAUCE:
2 cups fresh or frozen raspberries
TO SERVE:
3 tablespoons chopped pistachios

PREPARE THE CRUST:
Mix crumbs and butter in medium bowl. Press into bottom of 8-inch diameter springform pan. Refrigerate crust while preparing mousse.

PREPARE THE MOUSSE:
Melt 6 oz. white chocolate in top of double boiler set over simmering water, stirring until smooth. Cool slightly.

Bring 3/4 cup of the sugar and water to boil in heavy medium saucepan, stirring until sugar dissolves. Continue boiling without stirring until candy thermometer registers 238 degrees (soft-ball stage).

Meanwhile, using electric mixer fitted with clean dry beaters, beat egg whites with cream of tartar in large bowl until soft peaks form.

Gradually beat hot syrup into whites. Continue beating until mixture is stiff and glossy and bottom of bowl cools to barely lukewarm, about 3 minutes.

Fold in warm chocolate. Refrigerate chocolate mixture until cool but not set, about 5 minutes.

Whip cream, 1 tablespoon of the Grand Marnier, and vanilla in another large bowl until soft peaks form. Gently fold cream into chocolate mixture. Fold in chopped white chocolate. Pour mixture into crust; smooth top with spatula. Sprinkle top with chopped pistachios.

Freeze until firm, about 6 hours. (Can be prepared 3 days ahead; cover with plastic.)

PREPARE THE RASPBERRY SAUCE:
Puree raspberries in food processor or blender. Strain into medium bowl to remove seeds. Stir in remaining 1/4 cup sugar and remaining 2 tablespoons Grand Marnier. Refrigerate until well chilled, about 1 hour. (Can be prepared 3 days ahead; cover).

TO SERVE:
Remove pan sides. Cut dessert into wedges. Serve with raspberry sauce.