Preparation

Make the buns

• In a stand mixer fitted with the paddle attachment, mix the flour, sugar, and baking powder at low speed. In a medium bowl, combine the water, cream, and yeast and whisk to dissolve. Add the wet ingredients to the dry ingredients and mix on medium speed until the dough comes together, about 10 seconds. Switch to the dough hook and mix on medium speed until the dough looks smooth and feels tacky, 3 to 5 minutes.
• Lightly coat a medium bowl with oil and transfer the dough to it. Cover with plastic wrap and let rest at room temperature for 30 minutes.
• Divide the dough in half and roll each half into a 16-inch-long rope. Cut each rope into 8 equal pieces. Using your hands, gently flatten each piece into a 2-1/2 x 3-1/2-inch oval that’s 1/4 inch thick. Lightly oil a large rimmed baking sheet. Brush the top of each oval with oil, fold in half widthwise, and arrange in a single layer on the sheet. Cover loosely with plastic wrap and set them in a warm spot until puffy and roughly doubled in thickness, about 1-1/2 hours.

Parcook the lobsters

• Put about 1 inch of well-salted water in a 16- to 20-quart steamer pot, cover, and bring the water to a rolling boil. Meanwhile,kill the lobsters(optional).
• When the pot fills with steam, put in the lobsters: Holding them by the body, arrange them two by two on top of each other, facing in different directions so the steam can circulate around them easily.
• Cover the pot and steam the lobsters for 6 minutes for 1-lb. lobsters, 2 minutes longer for each additional 1/4 lb.
• Using tongs, transfer the cooked lobsters to a rimmed baking sheet and let sit at room temperature until they’re cool enough to handle. Remove the rubber bands from the claws and then remove the meat from the shells (reserve the shells and bodies for makinglobster stock, if you like).
• Cut the meat into bite-size pieces. Set aside.

Steam the buns

• Soak the bottom layer of a 2-tiered 10-inch bamboo steamer in water for at least 20 minutes before steaming the buns so that it doesn’t burn.
• Fill a 14-inch wok with enough water to just touch the bottom edge of the steamer (about 4 cups). Bring to a boil.

• Line both tiers of the steamer with rounds of parchment that have been perforated in several places with a hole punch or skewer. Arrange 4 of the buns on each tier of the steamer. Put the soaked tier in the wok, and stack the second tier on top. Cover and steam the buns until they’re puffed up and less tacky, about 15 minutes, checking occasionally to make sure the water hasn’t boiled away. Transfer the steamed buns to a baking sheet, gently open them, and cover with foil. Replenish the boiling water in the wok and steam the remaining buns.
• The buns can be served warm or at room temperature, but if they’re not going to be served within 2 hours, they should be frozen. Defrost by steaming or microwaving, covered with a damp paper towel, for 30 to 60 seconds.

Poach the lobster meat

• In a 2- to 3-quart saucepan, dry-toast the chiles over medium heat, stirring occasionally, until they darken, 1-1/2 to 2 minutes. Add the butter. Once it has melted, add the Sriracha and lemon juice. Turn the heat to low, add the parcooked lobster meat, and stir occasionally until the lobster is just cooked through, 2 to 3 minutes. Remove from the heat, discard the chiles, and season to taste with salt.

Assemble the bao

• With a slotted spoon, distribute the lobster meat among the buns. Serve immediately.