Place eight 4- to 6-ounce ramekins or 6-ounce custard cups in a shallow baking pan; set aside.
In a small bowl sprinkle gelatin over the water. Do not stir. Let stand for 5 minutes.
Meanwhile, in a medium saucepan stir together the whipping cream, sugar, vanilla bean and vanilla seeds, if using. Heat over medium heat until hot but not boiling. Add gelatin mixture; stir until gelatin is dissolved. Remove from heat. Remove and discard vanilla bean. Stir in buttermilk and vanilla, if using. Pour into ramekins. Cover and chill for 4 to 24 hours or until set.