Preheat your oven to 400°F and line a baking sheet with parchment paper.

In a medium saucepan, combine 1 cup water, 1/2 cup unsalted butter, and 1/4 teaspoon salt. Bring the mixture to a boil over medium heat.

Add 1 cup all-purpose flour all at once and stir vigorously until the dough forms a ball and pulls away from the sides of the pan.

Allow the dough to cool for about 5 minutes before adding the eggs to prevent them from cooking.

Add 4 large eggs one at a time, beating thoroughly after each addition until the dough becomes smooth and glossy.

Using a spoon or piping bag, drop 8-10 mounds of dough onto the prepared baking sheet, spacing them 2-3 inches apart to allow for expansion.

Bake in the preheated oven for 25-30 minutes until the cream puff shells are beautifully golden brown and puffed up.

While the shells are baking, prepare the vanilla cream filling by mixing 2 cups cold whole milk with the instant vanilla pudding mix. In a separate bowl, beat 1 cup heavy whipping cream with 1/4 cup powdered sugar and 1 teaspoon vanilla extract, then gently fold it into the milk mixture.

Once the shells have cooled, slice them horizontally, fill with the vanilla cream filling, and replace the tops.

Finish by dusting with additional powdered sugar or drizzling with melted chocolate if desired.