The Preparation
Preheat oven to 375°F
Combine milk, water, butter, and salt in a saucepan; bring to a boil
Add flour all at once and stir vigorously until dough forms a ball and pulls away from sides
Transfer to a mixing bowl and let cool slightly
Add eggs one at a time, beating well after each addition
Fold in grated cheese, cayenne, and mustard powder
Scoop or pipe dough onto parchment-lined baking sheet
Bake at 375°F for approximately 25 minutes until puffed and golden
