Step 1

Lightly grease two baking sheets; set aside. In a medium saucepan, combine the water, butter, and salt. Bring to boiling. Add flour all at once, stirring vigorously. Cook and stir until mixture forms a ball. Remove from heat. Transfer to a large mixing bowl. Cool for 10 minutes. Add eggs, one at a time, beating with an electric mixer on medium speed for 1 minute after each addition. Stir in Gruyere cheese, mustard, white pepper, and the 1/8 teaspoon cayenne pepper.

Step 2

Preheat oven to 400F. Using a pastry bag fitted with a 1/2-inch star tip, pipe batter in 1-inch mounds about 11/2 inches apart onto the prepared baking sheets. (Or use 2 teaspoons batter for each puff.)

Step 3

Bake for 20 to 25 minutes or until puffed and golden brown. Serve warm. If desired, sprinkle with additional cayenne pepper. Makes about 60 gougeres.