In a medium saucepan, combine 1 cup water, butter, sugar, and salt; bring to a boil over medium-high heat. Reduce heat to low, and sift in flour, stirring for 1 minute.
Transfer flour mixture to bowl of an electric mixer fitted with a paddle attachment. On low speed, add eggs, 1 at a time, beating until incorporated after each addition; spoon mixture into a pastry bag fitted with a large open-star tip.
Heat 4 to 5 inches oil in a large Dutch-oven until it registers 325 degrees.on a deep-fry thermometer. Holding pastry bag a few inches above the oil, squeeze out batter, snipping off 4-inch lengths with a knife or kitchen shears. Fry, flipping once, until deep golden brown all over, about 4 minutes. Using a slotted spoon, transfer churros to a paper towel-lined baking sheet to drain.
Roll churros in confectioners' sugar. Serve immediately with Chocolate Dipping Sauce.