01 - Whisk together the soy sauce, honey, hoisin sauce, rice vinegar, brown sugar, sesame oil, garlic, ginger, and red pepper flakes in a medium bowl until thoroughly combined.
02 - Arrange chicken drumsticks in the slow cooker. Pour the prepared glaze over the meat, turning each piece to ensure even coating on all sides.
03 - Cover and cook on low setting for 4 hours or until chicken reaches an internal temperature of 165°F and meat is tender enough to pull from the bone easily.
04 - Transfer drumsticks to a serving platter using tongs. Cover loosely with aluminum foil to maintain warmth while preparing the sauce.
05 - Pour the cooking liquid from the slow cooker into a small saucepan. In a separate bowl, whisk cornstarch and water together until smooth to create a slurry.
06 - Stir the cornstarch slurry into the saucepan with the cooking liquid. Bring to a boil over medium-high heat, stirring constantly for 2-3 minutes until sauce reaches desired consistency.
07 - Brush or spoon the thickened sauce generously over the drumsticks. Sprinkle with sliced scallions and sesame seeds immediately before serving.