Preheat the Grill pan: Add olive oil and butter. Add the drumsticks, sprinkle with salt, white pepper, and dried rosemary. Cover with foil. Grill for ten minutes per side on low heat. The internal temperature must reach 74 Celsius and must not be pink on the inside. Remove the chicken from the pan and let it rest for a few minutes.
Make the Yangnyeom sauce: Add Honey, Ketchup, Minced garlic, Gochuchang, Oyster sauce, and rice vinegar to a bowl. Add two tablespoons of water. Mix well. Add to a small pan on low heat. Cook until the sauce bubbles. Remove from the heat and coat the drumsticks with the sauce.
Garnish: Serve with parsley and freshly squeezed lime juice.