Whisk warm milk or water with sugar and instant yeast. Let it sit for 5 minutes until foamy.

In a large bowl, combine flour, salt, and baking powder. Stir in the yeast mixture and oil until it forms a shaggy dough.

Knead by hand for 8 to 10 minutes or use a stand mixer with a dough hook for about 6 to 7 minutes, until the dough is smooth and a bit bouncy.

Lightly oil the bowl, place the dough back in, cover, and let it rise for 60 to 75 minutes or until doubled.

After the first rise, punch down the dough to remove air, then divide into 10 to 12 pieces. Shape each into a tight ball, cover, and rest for 10 minutes.

Warm a pan with a little oil, then sauté onion and garlic until soft and aromatic.

Add the chopped chicken, soy sauce, oyster sauce, hoisin, brown sugar, pepper, bay leaf, and star anise if using.

Simmer on low for 10 minutes until the chicken is cooked through and the flavors meld.

Remove the bay leaf and star anise. Stir in the cornstarch slurry and cook for 1 to 2 minutes until glossy and thick. Let it cool before filling your dough.

Roll each dough ball into a small circle, thicker in the center and thinner at the edges.

Spoon in about 1 to 2 tablespoons of filling and an egg wedge if you’re using one.

Pleat the edges over the filling and pinch to seal. Place each bun seam side down on a parchment square.

Cover and let them proof for 20 to 25 minutes until slightly puffy.

Prepare the steamer: bring water to a simmer and add 1 tablespoon of rice vinegar. Wrap the steamer lid with a kitchen towel to catch drips.

Arrange buns with space between them as they will expand. Steam over medium heat for 12 to 15 minutes. Turn off the heat and let them sit for 3 minutes before opening the lid.