1. In a medium saucepan combine sugar and cornstarch whisking to thoroughly incorporate. Add milk and whisk until dry ingredients are dissolved. Next, whisk in the egg yolk and cream.
2. Place the pan over medium heat, whisking constantly until the mixture comes to a full boil and thickens.
3. As soon as the mixture thickens, remove the pan from the heat and whisk in the Baileys Irish Cream and vanilla.
4. Add chocolate and whisk until it is completed melted and smooth.
5. Pour pudding into individual serving dishes. Let the pudding cool slightly then cover the tops with plastic wrap to prevent a skin from forming. Refrigerate for at least 2 hours before serving.
6. If desired, garnish with fresh whipped cream and chocolate curls.