In a large mixing bowl, combine all-purpose flour, instant dry yeast, sugar, salt, and roasted sesame seeds. Make a well in the center and gradually add warm soy milk and toasted sesame oil. Knead the dough for about 8-10 minutes until it becomes smooth and elastic. Shape the dough into a ball, cover it with a damp cloth, and let it rise in a warm place for at least 2 hours or until doubled in size.

Bring a pot of water to a boil, then add the vermicelli noodles and cook for 7-8 minutes until they soften. Drain and chop the noodles into smaller lengths. In a skillet over medium heat, add a splash of neutral oil, sauté chopped scallions, carrots, and shredded cabbage until they soften and turn bright in color, about 5 minutes. Stir in the chopped noodles, soy sauce, and additional salt to taste; cook for another 2-3 minutes until well combined.

After the dough has risen, gently punch it down and divide it into 12-16 equal pieces. On a lightly floured surface, roll each piece into a circle approximately 4-5 inches in diameter, ensuring they are even. Lay the wrappers on a floured surface and cover them with a damp cloth.

Take one wrapper and place about 2-3 tablespoons of filling in the center. Gather the edges of the dough around the filling, pinching them together to seal, and twist gently at the top to secure the bun. Repeat for the remaining wrappers and filling.

In a skillet, heat a tablespoon of neutral oil over medium-high heat. Place the buns in the pan, leaving space between them, and cook for about 3-4 minutes until the bottoms are golden brown and crispy. Carefully add a splash of water to the pan, cover it with a lid, and steam the buns for an additional 5-6 minutes until they are cooked through and fluffy.

Remove the buns from the pan and place them on a serving platter. These vegan pan-fried buns with cabbage and vermicelli are best served hot.