Step 1: In a medium saucepan, combine the butter, water, milk, salt, and 2 teaspoons sugar over medium heat. Cook until the butter has fully melted and the mixture comes to a gentle boil.
Step 2: Add the flour all at once, stirring quickly with a wooden spoon until a smooth dough forms and pulls away from the sides of the pan. Continue stirring for another minute to slightly dry the dough.
Step 3: Transfer the dough to a large mixing bowl and let it cool for a few minutes.
Step 4: Add the eggs one at a time, mixing well after each addition until each egg is fully incorporated before adding the next. The dough should be smooth and glossy.
Step 5: Preheat the oven to 400°F (200°C) and line a baking sheet with parchment paper.
Step 6: Using a spoon or piping bag, shape the dough into small mounds on the baking sheet, leaving space between each one.
Step 7: Bake for 20–25 minutes, or until puffed and golden brown. Avoid opening the oven during baking to prevent collapse.
Step 8: Remove from the oven and let cool completely before filling.
Step 9: In a separate bowl, whip the heavy cream with the vanilla and 2 tablespoons sugar until stiff peaks form.
Step 10: Gently cut the puffs in half and fill them with the whipped cream using a piping bag.
Step 11: Dust the tops with powdered sugar just before serving.