1. Heat the milk and vanilla bean over medium heat just until the milk starts to boil. Remove from heat and set aside.

2. In a bowl, mix the butter, sugar, flour and salt to make a paste.

3. Whisk this mixture into the hot milk and stir until smooth. Return pot to the heat and cook briefly, stirring constantly, for 2 minutes.

4. Remove from the heat and add butterscotch chips. Mix until chips are fully melted and smooth.

5. Whisk in the yolks 1 at a time until incorporated, followed by the whiskey.

6. Cook for 2 minutes, stirring constantly, then remove from the heat.

7. Strain through a fine mesh strainer and cool.

8. Whip the egg whites in a mixing bowl to soft peaks.

9. Add the sugar, cornstarch, and cream of tartar.

10. Whip the whites again to stiff peaks.

11. Fold half of the egg whites into the soufflé base.

12. Add this mixture to the bowl of remaining egg whites and gently fold until the whites are just barely incorporated.

13. Pour the batter into 6 small souffle cups that have been lightly buttered and dusted with sugar, filling each cup only 3/4 of the way full.

14. Bake at 400 degrees for about 9 to 12 minutes, or until fully risen. Serve immediately.