Pâte à Choux

In a medium saucepan, combine butter, sugar, salt, and 1 cup water. Bring to a boil over medium-high heat, and immediately remove from heat. Using a wooden spoon, quickly stir in the flour until combined. Return pan to medium-high heat, and cook, stirring constantly, until mixture pulls away from the sides and a film forms on the bottom of the pan, about 3 minutes.

Transfer mixture to the bowl of an electric mixer fitted with the paddle attachment. Mix on low speed until slightly cooled, about 1 minute. Increase the speed to medium, and add the whole eggs, one at a time, beating until each is incorporated before adding the next. Test the batter by touching it with your finger and lifting to form a soft peak. If a soft peak does not form, the batter needs more egg. If you have added all the whole eggs and the batter still does not form a soft peak, lightly beat the remaining egg white, and add a little at a time. Use immediately.

The dough is best prepared in a heavy-bottom saucepan. Once the butter has melted, flour is added all at once and vigorously stirred to combine.