Split vanilla bean down the middle and scrape out the insides. Heat half-and-half and vanilla bean (all of it, including the husk) on medium-high until it just comes to a boil. Remove from heat, cover, and allow to rest for 15 minutes.
Whisk egg yolks and 2/3 cup of sugar together with butterscotch liqueur. Gradually stream some of the hot cream and vanilla mixture into the bowl while constantly stirring. Keep stirring to keep egg from scrambling. Continue until both mixtures are fully incorporated.
Pour mixture through a fine mesh strainer and equally divide between 6 ramekins. Place the ramekins in a deep baking pan. Add enough water to come to halfway up the side of the ramekins.
Cook in oven for 45 minutes, until the surface is set but still trembling when shaken.
Allow to cool slightly, then move to refrigerator to cool for at least 2 hours and up to 3 days.
When ready to finish, remove from refrigerator and place at room temperature for at least 30 minutes. Distribute 1 tablespoon of sugar on the surface of each ramekin. Gently rotate and tap the sides of each ramekin if necessary.
Using a brulee torch set to the highest setting, gradually melt the sugar on the surface of each ramekin. The sugar will bead up and turn to liquid form; move the torch to another area if the sugar starts to blacken. Some blackening is desirable. After going over the surface, some unmelted sugar will remain. Go back over these areas with the torch until they're melted, but stop if it turns black.