In a mixing bowl, combine flour, baking powder, and salt. Gradually add water and sugar, mixing until a dough forms. Knead the dough for about 5-7 minutes until smooth. Cover and let it rest for 30 minutes.

Prepare the Chicken

In a bowl, marinate the chicken thighs in buttermilk for at least 1 hour (or overnight for best results). After marinating, coat the chicken with cornstarch, shaking off excess.

Fry the Chicken

Heat vegetable oil in a deep frying pan over medium-high heat. Fry the chicken in batches until golden brown and cooked through, about 6-8 minutes per side. Remove and let drain on paper towels.

Prepare the Spicy Mayo

In a small bowl, mix mayonnaise, sriracha, and lime juice until well combined. Adjust spiciness to taste.

Prepare the Slaw

In a large bowl, combine shredded cabbage, shredded carrot, and kimchi. Toss together and set aside.

Steam the Bao Buns

Divide the dough into small pieces and roll them into flat circles. Place each circle on a small piece of parchment paper and steam for 10-12 minutes until fluffy.

Assemble the Bao Buns

Place a piece of fried chicken in each steamed bao bun. Top with the spicy mayo, slaw, and chopped scallions.