In a heavy-bottomed pot, combine butter, sugar, water, and vanilla extract. Place over medium heat until the mixture reaches a boil.

Once boiling, promptly add the flour, stirring continuously until the mixture pulls away from the sides of the pot, forming a cohesive ball.

Remove the pot from heat and allow the dough to cool slightly.

Gradually incorporate the eggs, one at a time, into the dough, ensuring each is fully integrated before adding the next.

On a baking sheet lined with parchment paper, portion out the dough, using either two spoons or a pastry bag, as preferred.

Preheat the oven to 400°F (204°C). Once heated, place the baking sheet in the oven for 15 minutes. After this time, reduce the temperature to 350°F (177°C) and continue baking for an additional 15 minutes.

Upon removal from the oven, swiftly make a small incision on the side of each cream puff to allow the escape of steam. Allow to cool thoroughly.

In a mixing bowl, combine the heavy cream, instant vanilla pudding, and milk. Using an electric mixer, beat the mixture until it achieves a thick consistency resembling whipped cream.

Once the shells have cooled, they may be sliced open and filled with the prepared filling. It is recommended to either pipe or spoon the filling into each shell.

For a refined finish, a light dusting of powdered sugar can be applied atop each cream puff.