1. Wisk together sauce ingredients. Place chicken in a large (2-gallon) ziptop bag. Add 1/2 cup of sauce, seal, turn to coat and refrigerate for up to 2 days. Refrigerate remaining sauce.
2. Preheat oven to 375°F. Line a rimmed baking sheet with foil. Arrange chicken on baking sheet; bake 35 minutes, turning once.
3. Heat outdoor grill to medium-high heat. Grill chicken, turning & basting frequently with 1/2 cup of reserved sauce, until cooked through, about 15 minutes. Transfer to a platter and serve with remaining sauce.