Preheat the barbecue to 350 degrees F. Generously butter a 6-cup soufflé dish (or small individual soufflé dishes) and sprinkle the dish with sugar; roll the dish around to coat all surfaces, then tap out the excess. Add a buttered and sugared aluminum foil collar that extends 2-3-inches above the rim of the dish and tie in place with butcher’s twine.
On your BBQ grill or on your stove top, heat the cream and 1/4 cup sugar in a medium saucepan over medium heat, stirring until the sugar dissolves. Add 6 ounces of white chocolate and stir until the chocolate dissolves. Whisk in egg yolks and orange peel, and cook for about five minutes or until the mixture thickens slightly, stirring constantly; do not boil.
Whisk in the Grand Marnier. Transfer the mixture to large bowl and, using an electric mixer, beat the egg whites and cream of tartar in large bowl until soft peaks form. Add 2 tablespoons of sugar and then beat again until stiff peaks form.
Mix 2 ounces of the chopped chocolate into the warm egg yolk mixture, then fold in the egg whites in 2 batches. Transfer the mixture to your prepared soufflé dish. Bake over INDIRECT heat in the BBQ until the soufflé is puffed and the top is golden brown, about 35 minutes. Dust with powdered sugar and serve.
This moist, orange-flavored soufflé is rich with white chocolate. Offer snifters of orange liqueur, with a mandarin orange segment and cherry on a toothpick floating inside, to sip with the dessert.
