Preheat oven to 375°F. Line a baking dish with foil or parchment paper.
In a bowl, whisk together soy sauce, honey, oil, vinegar, garlic, ginger, and red pepper flakes.
Place drumsticks in the baking dish and pour the marinade over them. Turn to coat evenly.
Bake uncovered for 45 to 50 minutes, flipping halfway through and basting with pan juices.
Broil for 2-3 minutes at the end for extra caramelization, if desired.
Garnish with chopped green onions and sesame seeds before serving.