
These vegan char siu bao are filled with savory-sweet barbecue tofu and wrapped in a soft, fluffy homemade dough. Baked until lightly golden, they make a satisfying dim sum-style snack, lunch, or party appetizer.
Make the starter for the dough. In a large bowl, stir together 1/2 cup warm water, the yeast, and a little of the flour until smooth. Set it in a warm spot for 15 minutes, or until the mixture looks foamy and active.
Add the coconut oil to the yeast mixture and stir until fully melted and combined, then mix in the remaining 1/2 cup warm water. Add the rest of the flour, vital wheat gluten, sugar, and a pinch of salt. Mix until a shaggy dough forms, then knead for about 10 minutes until fairly smooth. Cover and let rise for 1 hour, or until puffy.
While the dough rises, prepare the filling. Heat the oil in a wok, cast-iron skillet, or heavy pan over medium-high heat. Add the onion and tofu, then cook for 3 to 5 minutes until the tofu is lightly browned on one side. Turn gently and cook until the other side is lightly browned as well.
Season the filling with soy sauce, dark soy sauce, sugar, salt, sesame oil, hoisin sauce, and white pepper. Pour in the water or vegetable stock, then sprinkle in the flour. Stir gently so the tofu keeps some texture.
Simmer the filling for a few minutes, stirring, until the liquid thickens into a glossy sauce that coats the tofu. Remove from the heat and let the filling cool completely before assembling the buns. If it still seems loose, chill it briefly to firm it up.
Once the dough has risen, transfer it to a lightly floured surface and knead for 2 to 3 minutes to remove excess air. Divide the dough into 10 equal pieces and keep them covered with a damp towel so they do not dry out.
Flatten each piece into a round disc, leaving the center slightly thicker than the edges. Spoon about 2 tbsp of filling into the middle, then bring the edges up and pinch tightly to seal. Place each bun seam-side down on a parchment-lined baking sheet.
Keep both the shaped buns and any unworked dough covered with a damp towel as you go. Let the assembled buns rest for 10 minutes while you preheat the oven to 375°F (190°C).
Stir a little sugar with warm water to make a glaze and brush it over the buns. Put the tray in the oven, immediately lower the temperature to 350°F (175°C), and bake for 20 to 25 minutes, until the buns are lightly golden. Brush again with the remaining glaze after baking and serve warm.
Cool the filling completely before shaping or the dough can tear and the buns may open while baking. If you do not have vital wheat gluten, you can leave it out, though the dough may be slightly less chewy. Leftover buns keep well in the refrigerator for 3 days and can be reheated in the oven or microwave.