Gua Bao (Taiwanese Pork Belly Buns)

Name: Gua Bao (Taiwanese Pork Belly Buns)
Prep time: 20 min
Cook time: 1 h
Total time: 1 h 20 min
Cuisine: Chinese
Ingredients: 2 cup all purpose flour; 125 ml water ( , or 140ml milk, 3.5% fat); 2 tsp. instant yeast; pinch of salt; 2 tbsp. of sugar ( , optional); 1 tbsp. vegetable oil ( , optional); pickled mustard green ( , minced and stir-fried); 1 cup toasted peanuts; 1 tbsp. sugar powder; Coriander leaves; 2 fresh thai pepper; 2 minced garlic; 1 tsp. minced scallion; 1 tbsp. light soy sauce; 1 tbsp. sesame oil; 1 kg pork belly ( , skin on); 1 cup fried shallots; 25 g rock sugar; 4 tbsp. light soy sauce; 3 tbsp. soy paste ( , or 2 tbsp. dark soy sauce); 4 tbsp. Shaoxing wine; 4-5 garlic cloves ( , sliced); 1/4 tsp. white pepper powder; 2 green onions; 1 tsp. Chinese five spice powder