Special equipment: 6- or 8-cup souffle dish
Place an oven rack in the lower third of the oven. Preheat the oven to 450 degrees F. Butter the souffle dish. Grease the bottom and sides of the dish with butter and then coat with 3 tablespoons of the sugar.
In a medium heavy saucepan melt 6 tablespoons of the butter over medium heat until foamy. Whisk in the flour and cook for 1 minute. Gradually whisk in the milk, cream and ground ginger. Cook, whisking constantly, until thick and smooth, about 2 minutes. Pour the milk mixture into a large bowl. Stir in the remaining 1/2 cup of sugar. Add the egg yolks, one at a time, whisking well after each addition. Stir in the crystalized and fresh ginger.
In a stand mixer fitted with a whisk attachment, beat the egg whites and cream of tartar until the mixture forms stiff peaks, about 2 minutes. Using a large spatula, fold the egg white mixture into the milk mixture. Pour the batter into the prepared dish. Place the dish on a rimmed baking sheet and bake, without opening the door, until puffed and golden, 20 to 25 minutes.
Using a pastry brush, brush the top of the souffle with edible gold dust and serve immediately.
*Edible gold dust is available at gourmet and specialty food stores.