In a large mixing bowl, combine the flour, yeast, sugar, and salt. Create a well, add warm soy milk and toasted sesame oil. Mix until a dough forms, knead for 5 minutes. Cover and let rise for at least 2 hours.

Soak vermicelli noodles in boiling water for 5 minutes, chop them. In a skillet, heat oil, sauté scallions, carrots, and cabbage for 5-7 minutes. Add noodles, soy sauce, salt and sesame oil, mix and cool.

Punch down the dough, divide it into 12-16 pieces, and roll each into a ball. Flatten each ball into a wrapper, keeping covered with a damp cloth.

Fill each wrapper with 2-3 tablespoons of filling, pinch and twist to seal. Arrange on a lined tray.

Heat oil in a frying pan, place the buns crease-side down. Cook for 4-5 minutes until golden, add water, cover and steam for 7-10 minutes.

Remove from the pan, let cool slightly, and serve hot with a dipping sauce.