Combine the butter, water, and vanilla in a medium saucepan and bring to a rolling boil.

Add the flour all at once and stir constantly with a wooden spoon until the dough thickens and forms a smooth ball.

Remove the pan from heat and let the dough cool for 5 minutes.

Beat in the eggs, one at a time, until the batter is smooth and shiny.

Preheat the oven to 400°F and line baking sheets with parchment.

Drop rounded tablespoons of dough onto the prepared baking sheets, keeping them about 2 inches apart.

Bake for 25–30 minutes or until puffed and golden brown. Do not open the oven door early.

Let them cool on a rack before slicing in half.

Beat the heavy cream, instant pudding powder, and milk in a mixer until thick.

Pipe or spoon the filling into each half of the cooled puffs.

Dust with powdered sugar before serving.