In a mixing bowl, combine gochugaru, gochujang, light brown sugar, minced garlic, grated ginger, soy sauce, and black pepper to create a flavorful marinade. Dice boneless, skinless chicken thighs and add them to the bowl, tossing until well coated. Allow the chicken to marinate for at least 10 minutes while you prepare the rest of your ingredients.

Heat 1 tablespoon of canola oil in a large skillet over medium-high heat. Add the Korean rice cakes and sauté them for about 3-4 minutes, until they are slightly crispy and golden. Once done, remove them from the skillet and set aside.

In the same skillet, add chopped onions and sauté over medium heat until they become soft and translucent, which usually takes about 3-5 minutes.

Add the marinated chicken mixture to the skillet, including the remaining marinade. Pour in ¼ cup of water to create steam and cover the skillet. Cook for 8-10 minutes, stirring occasionally, until the chicken is fully cooked and reaches an internal temperature of 165°F (75°C). If using, add the sautéed rice cakes halfway through the cooking process.

Once the chicken is cooked through, remove the skillet from heat and sprinkle a generous layer of low-moisture mozzarella cheese over the top. Preheat your broiler on high, then place the skillet under the broiler for about 2 minutes, or until the cheese is bubbling and golden brown.

Remove the Korean Fire Chicken from the oven, and sprinkle with chopped green onions. Serve immediately, ideally alongside steamed rice or a crisp salad.