Whisk together the confectioners' sugar, cocoa powder, cornstarch and salt in a saucepan (one with a spout if you have one). Make sure to mix it really well. Whisk the milk in slowly, you don't want any lumps. Add the vanilla seeds and pod. Place over medium heat and bring to a slight simmer. Cook until thickened, about 5 minutes.
Remove the vanilla bean and stir in the milk chocolate morsels until melted. Keep warm until serving.
Cocoa Bar Setup: Arrange or display all the various flavorings your guests will enjoy. If you know your guests will want to try multiple combinations, have espresso cups available, so the hot cocoa will last longer and guest won't feel so bad trying multiple cups.