Gougeres (Gruyère Cheese Choux Puffs)

Preheat the oven to 200C, line a tray with parchment, finely grate 90 g Gruyere, and beat 2 eggs in a small bowl. Heat 120 ml water, 60 g butter, and 1/2 teaspoon salt in a saucepan over medium heat. Once the butter has fully melted and the edges begin to bubble, lower the heat and add 80 g flour all at once. Stir rapidly until no dry flour remains, then keep cooking and stirring over low heat for 2 to 3 minutes. The dough is sufficiently dried when it gathers into one mass and leaves a thin film on the bottom of the pan. Transfer it to a bowl and cool for 3 to 5 minutes, until warm rather than hot enough to cook the egg. Add the beaten eggs little by little. After every addition, continue mixing through the separated stage until the dough becomes smooth and glossy again before adding more. Stop when a lifted spatula leaves a slow V-shaped trail. Fold in the cheese and 1/4 teaspoon black pepper. If the dough is still too stiff to pipe, use only a small spoonful of remaining egg to adjust it. Pipe small rounds onto the tray and press pointed tips flat with a damp fingertip for even expansion. Bake for 20 to 25 minutes until puffed and golden. Keep the oven door closed throughout so the steam supporting the hollow centers is not released before the shells set.