Mix honey, soy sauce, mirin, garlic, pepper flakes, and water until combined and set aside
Cut chicken thighs into chunks and add to a bowl
Add salt, pepper, and oil to the chicken
Cover chicken in corn starch and mix until fully coated
Cover a pan with 0.5 inch of oil and heat until hot
Add coated chicken to the pan and fry until golden and internal temperature reaches 165°F
Flip chicken halfway through cooking
Drain chicken onto a wire rack
Add butter to the same pan and melt
Pour in the sauce and scrape up any fond from the bottom
Let sauce simmer until bubbly and thick
Combine chicken back into the sauce and serve
