Baked Pork Buns

Name: Baked Pork Buns
Prep time: 2 h
Cook time: 60 min
Total time: 2 h
Yield: 12
Ingredients: Ingredients; Dough; 3 cups all-purpose flour; 1 tablespoon instant yeast; 1/4 cup sugar; 1/2 teaspoon salt; 1 cup warm milk (110°F/45°C); 1/4 cup unsalted butter, melted; 1 egg (for egg wash); Filling (Char Siu Pork); 1 lb char siu pork (Chinese BBQ pork), chopped into small pieces (store-bought or homemade); 1 tablespoon vegetable oil; 1 small onion, finely chopped; 2 tablespoons oyster sauce; 1 tablespoon soy sauce; 1 tablespoon sugar; 1 tablespoon cornstarch mixed with 2 tablespoons water (slurry for thickening); 2 teaspoons sesame oil; 1 tablespoon hoisin sauce