01 - In a large mixing bowl, combine ground chicken, egg, panko breadcrumbs, chopped green onions, soy sauce, mirin, grated ginger, minced garlic, salt, and black pepper. Mix gently until just combined—avoid overworking the meat to keep meatballs tender.
02 - Lightly wet your hands with water to prevent sticking. Form the chicken mixture into 16 evenly sized meatballs, approximately 1.5 inches in diameter.
03 - Heat vegetable oil in a large nonstick skillet over medium heat. Add meatballs in a single layer and cook for 8–10 minutes, turning occasionally to brown all sides evenly. Cook until internal temperature reaches 165°F. Transfer meatballs to a plate and set aside.
04 - Wipe the skillet clean. In a small bowl, whisk together soy sauce, mirin, sake, sugar, cornstarch, and water until cornstarch is completely dissolved.
05 - Pour sauce mixture into the skillet and bring to a simmer over medium heat. Stir constantly with a wooden spoon until sauce thickens and coats the back of the spoon, about 2 minutes.
06 - Return cooked meatballs to the skillet. Gently toss and stir to coat evenly with teriyaki sauce. Simmer for 2–3 minutes, allowing glaze to adhere and meatballs to heat through.
07 - Transfer glazed meatballs to a serving platter or serve over steamed white rice. Garnish with sliced green onions and toasted sesame seeds. Serve immediately while hot.