Preparation

● Day 2: In a saucepan over medium-low heat, gently heat the milk until it is warm to the touch, about 110 to 115 degrees. Pour the milk into the bowl of a stand mixer and gently stir in the yeast and sugar. Let the yeast proof until bubbles form on the surface, about 10 minutes. Affix the dough hook attachment to the mixer, and add the salt, baking powder, baking soda, melted lard or shortening and 1 cup flour on low speed. Continue adding 1 cup of flour at a time, until it is well incorporated and a ball forms on the hook. Continue to knead on low speed for 10 to 12 minutes.
● Grease a large mixing bowl with lard or shortening, place the dough in the bowl and cover with a clean towel. Place the bowl in a warm place and let rise until doubled in size, about 1 hour.
● Turn the dough out onto a large floured work surface and shape it into a long loaf. Slice the loaf into 2 equal halves. Roll each half into a 16-inch log 1-inch thick. Cut each log into 16 walnut-sized pieces. Roll piece into a ball and set them 2 inches apart on greased baking sheets. Cover the baking sheets with clean towels and let rise about 20 minutes.
● Roll out 1 dough ball onto a lightly floured work surface into a 4-inch long oval. Grease a smooth chopstick with lard or shortening and place crosswise in the center of the oval. Fold the top half of the oval over the chopstick to make a thick, U-shape. Use the chopstick to transport the bun to a greased baking sheet. Slide the chopstick out and repeat this process with the remaining dough balls. Let the buns rest 20 minutes to rise.
● To fill the buns, gently place 1 tablespoon of vegetable filling (recipe above) or seafood and pork filling (recipe above) in the fold of each bun.
● To steam the buns, fill a wok with 4 cups water over medium-heat and bring to a simmer.
● Meanwhile, line the trays of a bamboo steamer with parchment paper, poking a few holes in the paper to allow the steam to rise. Working in batches, fill the steamer trays with filled buns, leaving a bit of space between them to rise while they cook. Stack the trays, cover the steamer basket and place inside the wok over the simmering water. Steam 10 minutes, until the buns are cooked though. Add more water to the wok as needed. Place the steamed buns on a plate covered with a towel until ready to serve. Repeat until the desired amount of buns are cooked.
● Serve with Sriracha or soy sauce on the side.