Preheat the oven to 425°F (220°C).

In a saucepan, combine water, unsalted butter, kosher salt, granulated sugar, and white pepper. Bring to a boil over medium heat.

Once the mixture boils, remove it from heat and add all-purpose flour. Stir until the mixture pulls away from the sides of the pan.

Allow the mixture to cool slightly, then incorporate eggs one at a time, mixing well after each addition until smooth and glossy.

Fold in grated Gruyère cheese.

Drop tablespoonfuls of the batter onto a baking sheet lined with parchment paper, spacing them apart.

Sprinkle additional Gruyère on top of each puff.

Bake in the preheated oven for 25 minutes or until puffed and golden.