Cut the chicken thighs into bite-sized pieces. In a large bowl, combine the chicken with the marinade ingredients. Wrap the bowl and let it marinate in the refrigerator for 30 minutes.
2 lbs boneless, skinless chicken thighs, 1 tsp kosher salt, 1/2 tsp ground black pepper, 1 tbsp soy sauce, 1 tbsp mirin, 1 tbsp minced garlic, 1/2 tsp MSG salt
In the meantime, prepare the sauce in a separate bowl and set it aside.
2 tbsp soy sauce, 2 tbsp rice vinegar, 2 tbsp sugar, 1 tbsp corn syrup, 1 tbsp water, 1 tsp sesame oil, 1 tsp crushed red pepper flakes, 1/2 tsp ginger
Also mix together the potato starch and cornstarch in a separate bowl.
1 cup potato starch, 1/2 cup corn starch
Coat each piece of chicken evenly in the starch mixture, tapping off any excess. Let the coated chicken rest for 2-3 minutes.
Heat enough neutral oil for frying to 340°F (170°C). To test if the oil is ready, carefully add a small piece of the coated chicken. If it immediately bubbles and begins to fry, the oil is ready.
1-2 cups neutral oil for frying
Fry the chicken in batches for 5-6 minutes, or until lightly golden. Do not overcrowd the pan.
Remove the chicken and place it in a strainer set over a large bowl to catch any excess oil. Let it rest for 2-3 minutes.
Increase the oil temperature to 375°F (190°C). Fry the chicken a second time for 1-2 minutes, or until deeply golden and crispy. Transfer to a strainer set over a large bowl.
Heat 1 tbsp neutral oil in a woke or a large shallow pan over medium-high heat.
Add the onion and bell pepper. Stir-fry for about 1 minute.
1 small onion, diced, 1 red bell pepper, diced
Add the dried red chilies, gochugaru, mala powder (optional) and the white parts of the green onions. Stir-fry for 20-30 seconds, until fragrant.
1 bunch green onion, cut 2" long, 3-5 dried chile, sliced, 1-2 tsp gochugaru (Korean red pepper flakes), 1-2 tsp Optional: Mala powder
Reduce the heat to medium-low. Pour the prepared sauce. Once the sauce begins to lightly bubble (~30-45 seconds), add the fried chicken and toss until every piece is evenly coated with the sauce.
Garnish with roasted sesame seeds. Serve warm with steamed rice.
1 tsp Roasted sesame seeds