2In a large saucepan, combine 1 cup water, butter, and 1/2 tsp salt. Bring to a boil over medium-high heat. When butter has melted, add flour all at once, stirring vigorously with a wooden spoon. Reduce heat to medium; keep stirring until mixture has formed a smooth, thick paste and pulls away from sides of pan, about 3 minutes. Transfer to bowl of a stand mixer fitted with paddle attachment or to a large heatproof bowl.
3If using a stand mixer, add 4 eggs, 1 at a time, mixing on low speed until egg is incorporated and dough is smooth before adding the next egg.
