Combine butter, 3/4 cup brown sugar, and molasses in a medium saucepan. Cook over medium heat, stirring constantly, 5 minutes or until sugar dissolves.
Combine 1 3/4 cups milk and whipping cream in a separate saucepan. Split vanilla bean lengthwise. Scrape seeds from vanilla bean into saucepan; stir in bean pod. Bring just to a simmer over medium heat.
Remove and discard vanilla bean pod. Slowly whisk milk mixture into sugar mixture.
Whisk together egg yolks, remaining 1/2 cup milk, cornstarch, vanilla, and salt in a small bowl. Gradually stir about one-fourth of hot mixture into yolk mixture; add yolk mixture to remaining hot mixture, stirring constantly. Cook over medium heat, stirring constantly, 20 minutes or until thickened.
Remove from heat; pour into a 1-quart baking dish.
Place plastic wrap directly on surface of pudding; chill at least 8 hours.
Combine 1/2 cup brown sugar, bourbon, and water in a small saucepan. Cook over medium-low heat 7 minutes or until a candy thermometer reaches 23
Meanwhile, beat egg whites and cream of tartar at high speed with an electric mixer until stiff peaks form. Gradually drizzle in hot brown sugar syrup, beating at high speed 2 minutes or until thick and glossy. Mound meringue over chilled pudding, forming peaks with the back of a spoon. Broil 8 inches from heat 2 minutes or until meringue is browned.
