Heat oven to 375°F. Line a rimmed baking sheet (15X10X1-inch) with aluminum foil.

Cut off tips of chicken wings and discard tips. Cut wings at joints to make 2 pieces.

Arrange pieces on baking sheet in a single layer. Bake for 20 minutes.

Whisk together plum sauce, soy sauce, sherry, blackberry preserves, butter, ginger, sriracha, and garlic in a 3 1/2 to 4-quart slow cooker.

Add chicken wings and stir to coat wings with sauce.

Cover and cook on low for 4 hours or on high for 2 hours.

Serve in the slow cooker on low heat setting or transfer to a serving dish or bowl.

Optional: Pour liquid into a saucepan. Stir together cornstarch and 1 tablespoon of water. Whisk cornstarch slurry into the liquid. Bring to a slow boil and cook, stirring constantly, until thickened. Pour thickened glaze over wings.

Sprinkle cilantro and sesame seeds over wings just prior to serving.