In a large bowl, combine the chicken strips with buttermilk, salt, white pepper, and garlic salt. Mix well, cover, and let it marinate in the fridge for at least 1 hour.

Preheat your oven to a low heat (around 200°F) to keep the finished chicken warm. In a large pan, heat the vegetable oil until hot, using at least 1 litre (4 cups) for deep frying.

In a small bowl, whisk together the flour, salt, ground black pepper, garlic salt, celery salt, dried thyme, paprika, baking powder, and chilli flakes until well combined.

Remove the marinated chicken from the fridge. Dredge each piece in the crispy coating mixture, ensuring it's fully covered.

Fry the chicken in hot oil for about 3-5 minutes, or until they turn golden brown and are cooked through.

Transfer the cooked chicken to a tray and keep warm in the oven while you fry the remaining chicken.

In a saucepan, combine gochujang, honey, brown sugar, soy sauce, minced garlic, ginger, oil, and sesame oil. Stir, bring to a boil, then simmer for about 5 minutes until thickened.

Pour the sauce over the crispy chicken and toss gently to coat. Garnish with sliced spring onions, chilli flakes, and sesame seeds before serving.