Step 1: Prepare the Choux Pastry

• Preheat your oven to 400°F (200°C). In a saucepan, combine the water and butter over medium heat until the butter melts. Add the flour and salt, stirring vigorously until a dough forms and pulls away from the sides of the pan. Remove from heat.

Step 2: Incorporate the Eggs

• Let the dough cool for a few minutes, then add the eggs one at a time, mixing well after each addition until fully incorporated and the dough is smooth.

Step 3: Pipe the Choux Pastry

• Transfer the dough to a piping bag fitted with a large round tip. Pipe small mounds (about 1.5 inches in diameter) onto a baking sheet lined with parchment paper, leaving space between each puff.

Step 4: Bake the Choux Puffs

• Bake in the preheated oven for 20-25 minutes or until the puffs are golden brown and have risen. Avoid opening the oven door during baking. Once done, remove from the oven and let cool completely.

Step 5: Make the Vanilla Custard

• In a medium saucepan, combine the heavy cream, milk, and half the sugar over medium heat. In a separate bowl, whisk together the egg yolks, cornstarch, and remaining sugar. Gradually whisk in the warm cream mixture into the egg yolks. Pour the mixture back into the saucepan and cook over medium heat, stirring constantly until thickened.

Step 6: Chill the Custard

• Remove from heat and stir in the vanilla extract. Transfer the custard to a bowl, cover with plastic wrap (directly on the surface to prevent a skin from forming), and chill in the refrigerator until set (about 1-2 hours).

Step 7: Fill the Cream Puffs

• Once the choux puffs are cool and the custard is set, use a small knife or piping bag to carefully fill each puff with the vanilla custard.

Step 8: Caramelize the Sugar

• Just before serving, sprinkle about 1 teaspoon of granulated sugar on top of each filled cream puff. Using a kitchen torch, carefully caramelize the sugar until it forms a crispy, golden crust. Allow the caramel to cool and harden.