Measure flour and set aside

Bring water, butter, vanilla, sugar, and salt to a boil in a 3-qt. saucepan over medium-high heat, stirring occasionally.

Immediately remove from heat, and quickly stir in flour mixture all at once.

Return to heat and stir with a wooden spoon for 1 to 2 minutes, or until dough is smooth and forms a ball

Transfer dough to the bowl of an electric mixer and let cool 5 minutes.

Add eggs, 1 at a time, beating until mixture is smooth and glossy.

Prepare Cinnamon Sugar: whisk together ½ cup sugar and cinnamon in a shallow dish or pie plate, set aside.

Spoon dough into a pastry bag fitted with a closed rose tip (Wilton 1F or Ateco 846).

Carefully pipe dough into preheated oil, in 6-inch lengths. Use kitchen scissors or tongs to cut off dough from piping bag. Cook 2 or 3 churros at a time. Fry until golden brown, about 4 minutes per side.

Remove churros with tongs to a plate to cooling tray lined with paper towels. Roll churros in cinnamon sugar, and place on a cooling rack.

Repeat process with remaining dough.

Serve warm with dulce de leche or chocolate sauce for dipping if desired.