01 - Whisk together soy sauce, honey, hoisin sauce, rice vinegar, brown sugar, sesame oil, garlic, ginger, and red pepper flakes in a medium bowl until fully incorporated and smooth.
02 - Arrange chicken drumsticks in the slow cooker insert. Pour prepared glaze over the meat, turning pieces to ensure even coating on all sides.
03 - Cover and cook on low setting for 4 hours until chicken reaches 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 retain heat while preparing sauce.
05 - Ladle cooking liquid into a small saucepan. In a separate bowl, mix cornstarch and water until smooth to create a slurry.
06 - Bring sauce to boil over medium-high heat. Stir in cornstarch slurry while whisking constantly. Continue stirring for 2-3 minutes until sauce reaches desired consistency.
07 - Brush or spoon thickened sauce generously over each drumstick, ensuring all pieces are coated with the glossy glaze.
08 - Sprinkle sliced scallions and sesame seeds over glazed drumsticks. Serve immediately while hot.