Flaky Chinese Spring Onion (Scallion) Pancakes (蔥油餅)

Name: Flaky Chinese Spring Onion (Scallion) Pancakes (蔥油餅)
Prep time: 45 min
Cook time: 15 min
Total time: 1 h
Cuisine: Asian, Chinese
Ingredients: For the dough; 300g plain flour; 150g lukewarm water; 1/2 tsp salt; For the filling; About 100g spring onions, finely chopped; 5 shiitake mushrooms, finely chopped (optional); 50g plain flour (more if needed); 1/2 cup (120ml) vegetable oil; 1 tsp Chinese five spice; 1 tsp salt; For the dipping sauce; 1 tbsp light soy sauce; 1 tsp sesame oil; 1 tsp rice vinegar