Step 1: Prepare the Teriyaki Sauce. In a mixing bowl, combine soy sauce, brown sugar, honey, minced garlic, grated ginger, sesame oil, and rice vinegar. Whisk until the sugar has dissolved. If you prefer a thicker sauce, mix the cornstarch with water until smooth, then add it to the sauce mixture. Set aside a portion of the sauce for basting later.
Step 2: Marinate the Drumsticks. Place the chicken drumsticks in a large resealable plastic bag or a shallow dish. Pour the teriyaki sauce over the chicken, ensuring all pieces are well-coated. Seal the bag or cover the dish with plastic wrap, and refrigerate for at least 30 minutes, or up to 8 hours for deeper flavor.
Step 3: Preheat the Oven. Preheat your oven to 425°F (220°C). This high temperature will give your drumsticks a beautiful caramelization.
Step 4: Bake the Drumsticks. Line a baking sheet with aluminum foil or parchment paper. Arrange the marinated drumsticks on the baking sheet, making sure they are not touching. Bake in the preheated oven for 25 minutes.
Step 5: Baste and Continue Cooking. After 25 minutes, remove the drumsticks and baste them with the reserved teriyaki sauce. Return them to the oven and continue baking for an additional 15-20 minutes, or until the chicken reaches an internal temperature of 165°F (75°C) and the skin is crispy.
Step 6: Garnish and Serve. Once cooked, remove the drumsticks from the oven and let them rest for a few minutes. Garnish with sliced scallions if desired. Serve hot with your favorite sides.