2 1/2 cups vanilla wafer crumbs
1/4 cup firmly packed brown sugar
6 Tablespoons butter, melted
1/2 teaspoon unflavored gelatin
1/4 cup orange juice
2 1/3 cups heavy whipping cream, divided
6 ounces white chocolate, chopped
2 teaspoons orange zest
2 Tablespoons sugar
2 (12-ounce) packages fresh blackberries
6 Tablespoons orange marmalade
Preheat oven to 350ºF.
In a medium bowl, combine vanilla wafer crumbs and brown sugar.
Add melted butter, stirring to combine.
Press mixture into bottom and up sides of a 10-inch removable bottom tart pan.
Bake for 10 minutes; cool completely.
In a small bowl, soften gelatin in orange juice; let stand for 10 minutes.
In a small saucepan, bring 1/3 cup cream to a simmer over medium heat.
Add white chocolate; reduce heat to low, stirring until chocolate is melted and smooth.
Add gelatin mixture, stirring to dissolve.
Stir in orange zest.
Remove from heat, and let cool for 10 minutes.
Transfer to a large bowl.
Chill until mixture is beginning to thicken, but not set, stirring often, about 35 minutes.
In a medium bowl, beat remaining 2 cups cream at medium speed with a mixer until soft peaks form.
Gradually add sugar, beating until stiff peaks form.
Fold into white chocolate mixture.
Spoon into prepared crust.
Cover and chill for at least 4 hours or up to 3 days.
In a medium bowl, combine blackberries and marmalade, tossing gently to coat.
Spoon blackberries over mousse before serving.