Mix graham cracker crumbs, melted butter, and 2 tbsp sugar. Press into a 9-inch pie plate. Bake at 350°F for 10 minutes (or freeze for 20 mins). Cool completely.

In a saucepan, combine cranberries, 3/4 cup sugar, and orange juice. Simmer over medium heat for 10-12 mins until berries burst and sauce thickens.

Puree the cranberry sauce in a blender or pass through a sieve for a smooth texture (optional).

Sprinkle gelatin over 1/4 cup cold water; let bloom for 5 mins. Stir bloomed gelatin into the hot cranberry mixture until dissolved. Let cool to room temperature.

Whip 1.5 cups heavy cream with vanilla to stiff peaks. Gently fold 1/3 of the cream into the cooled cranberry mix, then fold in the rest.

Pour mousse into crust. Refrigerate 4+ hours or overnight until set.

Whip remaining 0.5 cup cream with powdered sugar. Top the pie and garnish with rosemary and cranberries before serving.