Step 1

Prepare the marinade. Thinly slice 1 (1/2-inch) piece ginger (no need to peel). Place in a small bowl, add 1/3 cup char siu sauce, 1 tablespoon oyster sauce, and 1/4 teaspoon five-spice powder if desired, and stir to combine.

Step 2

Marinate the pork. Transfer the marinade to a gallon-sized ziptop bag. Add 1 pound pork shoulder steaks and turn to coat. Seal the bag and marinate in the refrigerator at least 6 hours or up to 24 hours, flipping the bag once or twice.

Step 3

Heat the oven. Arrange a rack in the middle of the oven and heat the oven to 300ºF. Meanwhile, let the marinated pork sit out at room temperature. Line a rimmed baking sheet with aluminum foil and fit with an ovensafe wire rack.

Step 4

Prepare the pork for roasting. Remove the pork from the marinade, let the excess marinade drip off and scrape off any slices of ginger, and place on the rack. Pour the remaining marinade into a small bowl and stir in 1 tablespoon honey.

Step 5

Roast the pork until tender. Roast until the pork is tender and registers at least 180ºF on an instant-read thermometer, 2 to 2 1/2 hours total. Every 30 minutes, brush the pork with the honey glaze, flip, and brush the other side.

Step 6

Broil the pork. Remove the pork from the oven. Turn the oven on to broil on high. Brush the pork with glaze. Broil until the top is just starting to char, 2 to 4 minutes. Flip the pork, brush with more glaze, and broil until the second side is just starting to char, about 2 minutes more. Remove from the oven and set aside to cool slightly.

Step 7

Prepare the sauce ingredients. Stir 1/4 cup char siu sauce, 1 tablespoon oyster sauce, and 1 teaspoon granulated sugar together in a small bowl. Finely chop 1/2 small yellow onion until you have 1/2 cup (save any remaining onion for another use). Dice the char siu into 1/4-inch pieces.

Step 8

Sauté the onion. Heat 1 tablespoon vegetable oil in a medium frying pan over medium heat until shimmering. Add the onion and cook until softened and starting to brown, 4 to 5 minutes. Meanwhile, stir 2 tablespoons water and 1 tablespoon cornstarch together in a small bowl.

Step 9

Finish the sauce. Add the sauce mixture and cook until simmering. Add the cornstarch slurry and cook until the liquid thickens considerably and sticks to the onion, about 30 seconds.

Step 10

Mix in the char siu. Remove from the heat, add the char siu, and stir to combine.

Step 11

Scoop and chill the filling. Divide and scoop the dough out onto a baking sheet or large plate in 15 portions (about 1 1/2 tablespoons each). Refrigerate uncovered while you make the bao dough, or refrigerate overnight if making buns the next day.

Step 12

Warm the liquids. Heat 1/2 cup whole milk and 1/4 cup plus 2 tablespoons water together in the microwave until just warm to the touch, about 20 seconds. (Alternatively, warm on the stovetop.)

Step 13

Mix the dry ingredients. Place 354 grams cake flour, 1/3 cup granulated sugar, 1 (1/4-ounce) packet instant yeast, and 2 teaspoons baking powder in the bowl of a stand mixer and whisk to combine.

Step 14

Mix the dough. Fit the dough hook onto the mixer. Turn a timer on for 10 minutes. Turn the mixer on to the lowest speed and slowly pour in the milk mixture. Check the dough after 2 minutes of mixing -- if it has not formed a ball, add more cake flour a teaspoon at a time (let it mix for a minute before adding more) until it forms one. Stop the mixer and timer and squeeze the dough after 5 minutes -- if it does not feel soft and supple and stretch easily, mix in a teaspoon of water (the dough may separate but will come back together after a minute or so). Continue timing and mixing until the 10 minutes is up. The dough should not stick to the bowl but should be smooth, soft, and supple.

Step 15

Let the dough rise. Cover the bowl and let rise in a warm place until slightly puffed, about 1 hour. When ready, the dough should feel like a soft marshmallow. Meanwhile, prepare the steam papers.

Step 16

Prepare the steam papers. Cut out 15 (3-inch) squares of parchment paper. Alternatively, flip 15 paper muffin liners inside out to flatten slightly and coat lightly with cooking spray or brush with vegetable oil.

Step 17

Divide the dough. Turn the dough out onto a work surface and divide into 15 pieces (38 to 40 grams each). Form each into a smooth ball (it’s best to pinch off a piece of dough and form immediately into a ball).

Step 18

Form the wrapper. Fill and form one bun at a time, keeping the remaining dough balls covered under a damp towel to keep them from drying out. Press a dough ball into a 3 1/2-inch wide disc (if the dough is sticky, dust your hands with cake flour). Pick up the disc and place it flat in your non-dominant hand. Gently flatten and stretch the edges with your other hand until the disc is about 4 inches wide with a slightly thicker center. (Alternatively, roll the dough out with a dumpling dowel.)

Step 19

Fill the bun. Place the wrapper on the work surface. Spoon a portion of filling onto the center of the wrapper, piling it high.

Step 20

Form a bundle. Bring up two opposite sides of the wrapper up and over the filling to meet in the middle. Pinch the dough together. Bring up the flat sides of the wrapper up and over the filling to meet in the middle. Pinch together to form a bundle with 4 corners.

Step 21

Fold in the corners. Pull two opposite corners of the bundle to the middle and pinch the dough together. Repeat with the remaining two corners and pinch to completely seal in the filling.

Step 22

Pinch and twist to seal. Pick up the bun in your non-dominant hand. Pinch the dough where all the pleats meet and twist this part toward you while at the same time twisting the bun away from you with your other hand. This will make the folds take on a more swirled look. Gently round out the bun with your hands if you’d like, then place on a parchment square. Repeat filling the remaining buns.

Step 23

Place the first round of buns in the steamer. Place as many buns will fit in a steamer with at least 2-inches of space between them (5 in a 12-inch steamer). Leave the rest of them on the counter or on a baking sheet.

Step 24

Let the buns rise. Cover the buns loosely with plastic wrap or a damp kitchen towel and let rise in a warm place for 30 minutes (they may puff a little but will not rise much).

Step 25

Prepare a steamer. Prepare a steamer for steaming and bring the water to a boil over medium-high heat.

Step 26

Steam the buns. Uncover the buns in the steamer. Cover with the steamer lid and steam until the dough is cooked through, about 10 minutes. Transfer to a plate. Steam the remaining buns, adding more water to the steamer between rounds if needed. Serve warm.