01 - In a medium bowl, whisk together the soy sauce, honey, hoisin sauce, rice vinegar, brown sugar, sesame oil, garlic, ginger, and red pepper flakes until thoroughly combined.
02 - Arrange the chicken drumsticks in the slow cooker. Pour the prepared glaze over the chicken, turning each piece to ensure even coating.
03 - Cover and cook on low heat setting for 4 hours, or until the chicken is fully cooked through and tender enough to pull from the bone easily.
04 - Transfer the drumsticks to a serving platter and cover loosely with aluminum foil to keep warm while preparing the sauce.
05 - Pour the cooking liquid into a small saucepan. Combine cornstarch and water in a separate bowl to create a slurry, then stir into the saucepan. Bring to a boil over medium-high heat, stirring constantly for 2-3 minutes until thickened.
06 - Brush or spoon the thickened glaze generously over the drumsticks. Garnish with sliced scallions and sesame seeds immediately before serving.