Slice your vanilla bean in half lengthwise using a sharp knife, then scrape out the seeds with the back of your knife.
Combine the milk, salt, vanilla bean seeds, and the scraped pod in a medium-sized saucepan. Heat over medium heat until it starts to steam, but do not let it boil.
While the milk is heating, take a large bowl, add the egg yolks and sugar. Whisk them together until the mixture becomes pale and thick. This process might take around 2-3 minutes.
Sift in the cornstarch to the egg yolk and sugar mixture and whisk again until everything is well combined and there are no lumps.
Once the milk is heated, remove the vanilla pod from the milk with tongs or a slotted spoon. Then, gradually pour the warm milk into the egg yolk mixture while continuously whisking to prevent the eggs from curdling.
Pour this mixture back into the saucepan and cook over medium heat.
Stir constantly until the mixture thickens. It should reach the consistency of a thick pudding.
Once thickened, remove the pan from heat. Add in the diced unsalted butter. Stir until the butter completely melts and incorporates with the mixture.
Cover the cream with a piece of plastic wrap pressed directly on the surface of the cream to prevent a skin from forming.
Chill the crème pâtissière in the refrigerator for at least 2 hours, or until it is completely cold.
In a tall glass or container, place white chocolate chips/ chunks, vanilla extract, and the bloomed gelatin, pour in warm heavy whipping cream and let it sit for 2-3 minutes.
Transfer to a container and cover it with plastic wrap, making sure that the plastic touches the surface of the mixture to prevent it from forming a skin.