Preheat oven to 350˚F.

Pat chicken dry with a paper towel, then season all over with salt and pepper.

Heat oil in an oven-safe skillet (preferably cast iron) over medium heat. Sear chicken thighs undisturbed, skin side down, until the skin is golden brown and crispy, 8-10 minutes. Flip and sear again until slightly golden, 3 minutes. Transfer chicken to a plate (it will not be fully cooked at this point) and set aside. Pour off all but 1 tablespoon of rendered chicken fat.

Melt butter in the same skillet over medium low heat, scraping up any bits with a spatula. Swirl the pan occasionally until butter is foamy, golden brown, and nutty, 3-4 minutes. Add honey, garlic, and chili flakes (if using) cooking until fragrant, 1 minute. Add in the lemon juice and season to taste with salt and pepper.

Add the chicken back into the browned butter, skin side up. Baste thighs with butter sauce. Transfer to oven and cook until the chicken registers an internal temperature of 165˚F, 5-7 minutes. Top with fresh parsley and serve immediately.