In a saucepan, combine water, butter, sugar, and salt. Bring to a boil.
Add the sifted flour all at once. Stir vigorously until the dough forms a ball and pulls away from the sides.
Transfer the dough to a bowl and let it cool slightly.
Mix in the egg and vanilla extract until the batter is smooth and glossy.
Place in a piping bag with a star tip. Pipe strips onto parchment paper and drop them into hot oil.
Fry until golden brown, then immediately toss them in the sugar mixture.
Serve warm with melted chocolate.
