Butter 8 1 cup souffle molds. Roll sugar around to coat.

Preheat oven to 400*F, and set the rack in the lower third level of the oven. To make the sauce base:

Melt the butter over a moderately low heat and whisk in flour. Cook, whisking, 3 minutes. Add the milk and cook over moderate heat, whisking, until mixture is very thick and pulls away from sides of pan. Transfer to a bowl and let cool for about 5 minutes.

In a large bowl whisk the yolks, vanilla, orange oil or zest and a pinch of salt, whisk in Grand Marnier and flour/butter mixture whisking until smooth.

In a clean, separate bowl, beat egg whites until foamy. (This is the tricky bit...any trace of grease will ruin your whites) Slowly add in the sugar, and beat to stiff shining peaks. When you lift the beater, the whites will be very stiff and will be able to stand up when the beater is pulled through them.

Finishing the souffle:

Stir in 1/4 of the egg whites to lighten it. Delicately fold in the rest of the egg whites and turn the souffle mixture into the prepared molds.

Place the ramekins in a baking pan and fill with hot water, half way up the sides. Bake at 400*F for about 20 minutes, until puffed and tops are golden.

Sprinkle with powdered sugar.