Jangeo gui (Gyeongsang style)

Carefully clean the Freshwater eel, removing any slime and gutting it if not already done. Butterfly the eel by cutting along its belly and flattening it, leaving the skin intact.

In a mixing bowl, combine the Gochujang, Gochugaru, Soy sauce, Mirim, Minced garlic, Minced ginger, Sugar, Sesame oil, and Black pepper. Mix thoroughly to create a smooth, spicy marinade.

Generously brush the marinade over both sides of the butterflied Freshwater eel. Allow the eel to marinate for at least 30 minutes at room temperature, or up to 2 hours in the refrigerator.