Heat oven to 400°F. Coat a baking sheet with non-stick cooking spray; set aside. Prepare bread mix according to package directions.
In a saucepan, heat oil on medium high and stir fry char siu for 30 seconds. Add onions, sugar, shoyu and salt. In a small bowl, mix flour and cornstarch with water. Stir into char siu. Cook until mixture thickens; cool.
Knead dough on a floured board until no longer sticky, about 1 to 2 minutes. Divide dough into 12 equal-sized pieces and flatten. Put a tablespoon of char siu mixture in center of each; form buns by pulling dough up and around filling. Pinch to seal seams. Place on prepared baking sheet. Cover loosely with a towel and let rise until doubled.
Bake buns for 13 to 15 minutes. Brush tops with honey while hot. Makes 12 buns.
Approximate Nutrient Analysis per bun:
450 calories, 10 g fat, 2.5 g saturated fat, 30 mg cholesterol, 850 mg sodium, 77 g carbohydrate, 1 g fiber, 25 g sugar, 13 g protein