Start by shredding or finely chopping the cooked beef pot roast into small pieces. Smaller pieces distribute more evenly inside each bun.
Place the beef in a microwave-safe bowl and heat until warmed through. This helps the beef absorb the sauce more effectively.
Add the chopped spinach or greens and hoisin sauce. Stir well until everything is evenly coated and the mixture becomes thick and glossy.
Line the bottom of your steamer basket with parchment paper. Cut small holes if needed to allow steam to circulate properly.
Fill the pot with water, ensuring the water level remains below the steamer basket. This prevents the buns from becoming soggy.
Bring the water to a steady boil while you assemble the buns.
Separate the biscuit dough pieces and place them on a lightly floured surface. Flatten each piece into a square approximately 3 inches wide.
Use your fingers to gently stretch the corners. Slightly thinner edges make sealing easier and create a more even bun shape.
Keep the dough pieces covered with a towel while working to prevent them from drying out.
Place about 1 tablespoon of the beef mixture in the center of each flattened dough piece. Avoid overfilling to keep the buns sealed during steaming.
Bring two opposite corners together over the filling and pinch them closed. Repeat with the remaining corners.
Seal all seams tightly to prevent the filling from escaping while cooking.
Arrange the filled buns in the prepared steamer basket, leaving at least 2 inches between them. They will expand as they cook.
Cover the steamer with a lid and steam for about 7 minutes. The dough should become fluffy and fully cooked.
Cook in batches if necessary to avoid overcrowding the steamer basket.
Carefully remove the buns using tongs and place them on a cooling rack. Let them rest for a few minutes before serving.
The brief cooling period helps the filling settle and makes the buns easier to handle.