Turn out the dough onto a floured surface. Divide it into 7 equal pieces. Keeping the other portions covered with a kitchen towel so they don’t dry out, roll each piece into a ball. Cover and let rest for 10 minutes. Using a rolling pin, flatten the balls into rounds that are 3½ to 4 inches in diameter. Place the buns on a baking sheet lined with parchment paper; put the sheet inside a large plastic bag and tie the open end closed. Leave the pan in a warm area until the buns have doubled in size, 30 to 45 minutes. Meanwhile, preheat the oven to 375 degrees.
04Remove the sheet from the bag, brush each bun with water and sprinkle the sesame seeds on top. Bake until golden brown, 20 to 25 minutes. Let cool at least 10 minutes. Slice in half and serve.