Prepare the Dough: In a medium saucepan, combine water, butter, sugar, and salt over medium heat. Stir until melted and bubbling.
Add Flour: Remove from heat and stir in flour until it forms a smooth ball.
Incorporate Eggs: Cool slightly, then add eggs one at a time, mixing well after each addition.
Pipe Crullers: Transfer dough to a piping bag fitted with a star tip. Pipe rings onto parchment-lined baking sheets.
Fry Crullers: Heat oil to 375°F (190°C) and fry each cruller until golden brown, about two minutes per side.
Glaze: Combine powdered sugar, milk, and vanilla for the glaze. Dip each cooled cruller into the glaze before serving.