In a large mixing bowl, whisk together the all-purpose flour, instant dry yeast, sugar, salt, and roasted sesame seeds until well combined. Create a well in the center and pour in the warm soy milk and toasted sesame oil. Mix until a dough forms, then knead on a floured surface for about 8-10 minutes until smooth and elastic. Place the dough in a greased bowl, cover with a damp cloth, and let it rise for 2 hours in a warm area, or until it has doubled in size.

While the dough rises, prepare the filling by soaking the vermicelli noodles in boiling water for about 5 minutes, then drain and chop them into small pieces. In a skillet, heat a tablespoon of neutral oil over medium heat. Add the chopped scallions, shredded carrots, and raw cabbage, cooking for about 5 minutes or until everything is tender and slightly translucent. Stir in the noodles, soy sauce, and any additional seasonings, mixing well. Drain any excess liquid to ensure your filling is not soggy.

Once the dough has risen, punch it down to release the air and transfer it onto a floured surface. Divide the dough into 12-16 equal pieces and roll each piece into a ball. Flatten each ball with your palm, then use a rolling pin to form a wrapper about 3-5 inches in diameter, ensuring the edges are thinner than the center.

Take one wrapper and place 2-3 tablespoons of the vegetable filling in the center. Pinch the edges of the wrapper together, folding it to create pleats, and twist to seal securely. Repeat this process with remaining wrappers and filling, placing the assembled buns on a floured tray to prevent sticking.

Heat a couple of tablespoons of oil in a large non-stick skillet over medium heat. Once hot, place the buns in the skillet, creased-side down, ensuring they are not overcrowded. Fry for about 4-5 minutes, until the bottoms are golden brown. Pour in a quarter cup of water, reduce the heat to low, and cover immediately. Steam the buns for approximately 6 minutes, or until all the water has evaporated.