1-First Step: In a large bowl, combine 3 cups all-purpose flour, 1 tsp instant yeast, 1 tsp sugar, and 1 tsp salt. Slowly pour in 1.5 cups warm water while stirring with chopsticks or a spoon until a shaggy dough forms. Turn onto a lightly floured surface and knead for 10 minutes until smooth and elastic. Place the dough in a greased bowl, cover with a damp cloth, and let rise in a warm spot for 1 hour until doubled. Punch down gently to release air.

2-Second Step: While dough rises, heat 1 tsp sesame oil in a skillet over medium heat. Add 2 minced garlic cloves and 1 tsp grated ginger; sauté 30 seconds until fragrant. Stir in 2 cups shredded cabbage, 1 cup chopped shiitake mushrooms, and 1 grated carrot. Cook 5 minutes until softened. Add 200g crumbled firm tofu, 2 tbsp soy sauce, 1 tsp cornstarch, salt, and pepper. Stir-fry 3-4 minutes until filling is dry and flavorful. Cool completely.

3-Third Step: Divide risen dough into 12 equal balls (about 60g each). On a floured surface, roll each into a 4-inch circle, thicker in center. Place 2 tbsp filling in middle, pleat edges to seal tightly, twisting top. Repeat for all. Let rest 15 minutes covered.

4-Fourth Step: Heat 2 tbsp neutral oil in a nonstick skillet over medium heat until shimmering. Arrange 6 buns seam-side up; fry 2 minutes for golden bottoms. Carefully add 1/2 cup water, cover immediately, reduce to medium-low, and steam 8-10 minutes without lifting lid.

5-Fifth Step: Uncover, cook 1-2 more minutes to crisp bottoms again. Use thin spatula to transfer to plate, bottoms up. Repeat batch.

6-Final Step: Garnish with chopped scallions, serve hot with chili oil or black vinegar.