In a large mixing bowl or using a stand mixer, combine the all-purpose flour, baking powder, baking soda, salt, and sugar. Gradually mix in water and egg until a shaggy dough forms. Knead the dough for about 7-9 minutes until it becomes smooth and elastic, then cover it with a damp cloth. Allow it to rest for 1 hour at room temperature, making sure it rises slightly.

After resting, transfer the dough to a lightly floured surface. Roll it out into a rectangle roughly 1 cm thick. Cut the dough into strips about 3 cm wide. For each pair, wet the center of one strip with a little water, place the second strip on top, and press firmly in the center to secure them together. This will create the iconic youtiao shape.

In a deep-fryer or a heavy-bottomed pot, heat oil to a temperature of 180-190°C (400°F). Use a kitchen thermometer to ensure the oil is just right for frying. The oil should ripple slightly when ready, indicating it's hot enough for the youtiao to cook perfectly and achieve that crispy exterior.

Gently stretch each assembled strip of dough slightly, then carefully slide them into the hot oil, working in batches to avoid overcrowding. Fry for about 1 minute on each side, turning with chopsticks until they transform into a beautiful golden-brown color.

Once they are nicely browned, use a slotted spoon to remove the youtiao from the oil. Allow excess oil to drain off by placing them on a wire rack or paper towels. Serve the youtiao hot, ideally alongside a bowl of warm soy milk for a classic breakfast experience that everyone will love!