In a saucepan, combine whole milk, heavy cream, ⅓ cup granulated sugar, vanilla bean, and ¼ teaspoon salt. Heat until just boiling.

In a separate bowl, whisk together egg yolks and cornstarch.

Gradually add the hot milk mixture to the egg yolk mixture, whisking continuously.

Return the mixture to the saucepan and cook over medium heat until thickened, stirring constantly.

Remove from heat and stir in 4 tablespoons of softened unsalted butter until melted. Let cool.

In a separate saucepan, combine water, ½ cup unsalted butter, and ¼ teaspoon salt. Bring to a boil.

Once boiling, remove from heat and stir in the flour until a dough forms.

Allow the dough to cool slightly, then beat in the 4 eggs one at a time until fully incorporated.

Preheat the oven to 400°F (200°C).

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

Bake for 25-30 minutes or until golden and puffed.

Let cool and fill with the cream filling. Dust with powdered sugar before serving.