Hot Grand Marnier Souffle

2/3 cup granulated sugar, divided
3 tablespoons Grand Marnier
2/3 teaspoon vanilla extract
6 large egg whites
? teaspoon cream of tartar
1/8 teaspoon salt
1 teaspoon powdered sugar

Heat oven to 300 and place a baking sheet on the middle rack.
Coat 6 ramekins with cooking spray and sprinkle each with 2 teaspoons granulated sugar, shaking to coat.
Place egg yolks in a large bowl. Beat with mixer at medium-high speed five minutes or until thick and pale.
Gradually add ? cup granulated sugar and bat two minutes. Beat in liqueur and vanilla.
Place egg whites in large bowl and beat with mixer at high speed one minute or until foamy. Add cream of tartar and salt and beat until soft peaks form.
Gradually add ? cup sugar, one tablespoon at a time, beating until stiff peaks form.
Gently stir one forth of egg mixture into liqueur mixture. Gently fold in the remaining egg mixture.
Divide mixture evenly among the prepared ramekins. Place ramekins on baking sheet in oven and bake at 400 for ten minutes until tall and golden brown. Quickly dust with powdered sugar.