1. Marinate the chicken wings in buttermilk, soy sauce, and garlic powder for at least 1 hour.
2. In a mixing bowl, combine flour, cornstarch, and baking powder. Gradually add cold water and whisk until smooth.
3. Heat oil in a deep fryer to 350°F (175°C).
4. Dip marinated chicken wings in the batter and fry until golden brown and crispy, about 10-12 minutes.
5. In a saucepan, combine gochujang, soy sauce, honey, rice vinegar, minced garlic, and sesame oil. Cook over medium heat until the sauce thickens.
6. Toss the fried chicken wings in the sauce until well coated. Serve immediately.