In a stand mixer, combine all-purpose flour, baking powder, baking soda, salt, and sugar. Add egg and water, knead for 7-9 minutes until smooth. Shape into rectangle, brush with oil, and let rest covered for 1-2 hours until doubled.

Turn the risen dough onto a floured surface, cut into strips about 3 cm wide. Press a line down the center of each strip. Layer two strips and pinch together.

Heat vegetable oil to 180-190°C (400°F) in a deep pan. Gently stretch each Youtiao strip and fry for about 1 minute on each side or until golden brown.

Serve warm with soy milk or congee.