In a saucepan, combine whole milk, heavy cream, vanilla bean and seeds, granulated sugar, cornstarch, and salt. Cook over medium heat until thickened, stirring constantly.

Remove from heat and whisk in egg yolks and cold butter until well mixed. Let cool.

In another saucepan, combine water, unsalted butter, granulated sugar, and salt. Bring to a boil.

Add flour all at once, stirring vigorously until the mixture forms a ball.

Remove from heat and allow to cool slightly. Add eggs one at a time, mixing well after each addition until the dough is smooth.

Preheat the oven to 425°F (220°C).

Drop spoonfuls of the dough onto a baking sheet lined with parchment paper.

Bake for about 20-23 minutes or until puffs are golden brown and hollow inside.

Let cool slightly, then fill with the pastry cream and dust with confectioner's sugar.