Instructions

1. Make the ginger water:
2. Cut 1 (1 1/4-inch) piece ginger into 1/4-inch-thick rounds (5 slices; no need to peel). Place in a small bowl and add 1/3 cup boiling water, 2 star anise pods, and 1 teaspoon dried red Sichuan peppercorns. Let sit until cooled to room temperature, about 20 minutes. Meanwhile, make the dough.
3. Make the dough:
4. Place 3/4 cup warm water, 3 tablespoons granulated sugar, 3 tablespoons vegetable oil, 1 teaspoon active dry yeast, and 1/8 teaspoon kosher salt in a large bowl and stir until the sugar is dissolved. Add 2 cups all-purpose flour, 3/4 cup cornstarch, and 2 teaspoons baking powder. Mix until a shaggy dough forms.
5. Transfer the dough onto a work surface and knead with your hands until smooth and elastic, about 10 minutes. If the dough is dry, dampen your hands while kneading. Return to the bowl, cover with plastic wrap or a damp kitchen towel, and let rise in a warm place until puffed and roughly doubled in bulk, about 1 hour. Meanwhile, make the filling.
6. Make the filling:
7. Finely chop 4 medium scallions until you have 1/4 cup and place in a medium bowl. Add 12 ounces ground pork, 2 teaspoons soy sauce, 2 teaspoons cornstarch, 1 teaspoon Shaoxing wine, 1/2 teaspoon dark soy sauce, 1/2 teaspoon kosher salt, 1/2 teaspoon granulated sugar, and 1/8 teaspoon ground white pepper. Mix with your hand in one direction until combined and sticky. Scoop up all the filling in one hand and throw it forcefully back into the bowl (this helps give it a bouncy texture).
8. Pour about half of the ginger water through a fine-mesh strainer over the filling. Mix again in the same direction until the water is absorbed. Repeat straining in the remaining ginger water and mixing it in. Add 1 tablespoon toasted sesame oil and mix in the same direction until combined. Cover and refrigerate until ready to assemble.
9. Cut 12 (3 1/2-inch) squares of parchment paper.
10. Assemble the buns:
11. Scoop out the filling into 12 (about 2-tablespoon) portions and place on a plate.
12. Transfer the dough to a work surface and roll out into a rough 12-by-13-inch rectangle (about 1/8-inch thick) with a shorter side closer to you, popping as many bubbles as possible. Starting at the bottom, roll the dough up into a tight log and arrange seam-side down. Cut crosswise into 12 pieces. Cover with a damp kitchen or paper towel.
13. Working with one piece of dough at a time, place it on a cut side, then press into a 2-inch-wide round. Roll out with a rolling pin or small dowel until 5 inches wide, then roll so that the outer 2 inches are thinner than the center and the wrapper is 6 inches wide.
14. Holding the wrapper flat in your non-dominant hand, drop a portion of the filling onto the center, cupping your hand slightly.
15. Pleat with your dominant hand: Place your thumb next to the filling and your index finger on the underside of the wrapper and lift that section up slightly. Use your middle finger to gather and pull the next section of wrapper toward your thumb to form a pleat. Pinch the pleat together.
16. Keeping your thumb in the same position the whole time and using your index finger to hold the last pleat in place, repeat using your middle finger to grab and fold more pleats, working your way around until all the wrapper is pleated. Use your non-dominant thumb to push the filling down as you pleat.
17. 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.
18. Steam the buns:
19. Fill a steamer with hot tap water. Place as many buns as will fit in the steamer basket with at least 1 1/2 inches of space between them (6 in a 12-inch steamer; the parchment can overlap slightly). Cover and let proof until puffed and slightly larger, about 30 minutes. Meanwhile, cover the remaining buns with the damp towel.
20. Leaving the buns in the steamer, return the water to a boil over high heat. Steam until the buns are puffed and fluffy and the filling registers at least 160ºF on an instant-read thermometer, about 15 minutes. Turn off the heat and let cool covered in the steamer for 5 minutes to prevent the buns from collapsing.
21. Transfer the steamed buns to a plate. Place the remaining buns in the steamer basket, cover, and let proof over the hot water until puffed and slightly larger, about 15 minutes. Return the water to a boil over high heat (check and add more water if needed before turning on the heat). Repeat steaming for 15 minutes and cooling in the steamer for 5 minutes.