In a large mixing bowl, combine flour, yeast, sugar, and salt. Add warm soy milk and toasted sesame oil, mixing until a dough forms.

Knead the dough on a floured surface for about 5-7 minutes until smooth.

Place the dough in a lightly oiled bowl, cover with a damp towel, and let it rise for at least 2 hours until doubled in size.

Soak vermicelli noodles in boiling water for 7-8 minutes, drain and chop them.

Heat neutral oil in a skillet over medium-high heat. Add cabbage, carrots, and scallions; sauté for 4-5 minutes.

Add chopped noodles, soy sauce, and salt; cook for another 2-3 minutes.

Punch down the risen dough, divide into equal pieces, and roll into small balls.

Flatten each ball into a round wrapper about 3-5 inches in diameter.

Place filling in the center of the wrapper, pinch and twist edges to seal.

Heat a non-stick skillet over medium heat, add oil, and arrange buns crescent-side down.

Cook for about 4-5 minutes until golden brown, then add water and cover to steam for 5-6 minutes.