In a medium saucepan over medium-high, melt butter. Add onion and garlic. Cook until onions are translucent, about 2 minutes. Add syrup, bourbon, ketchup, soy sauce, salt and black pepper. Cook until the sauce has reached a boil and is slightly thickened, 8 to 10 minutes
Reserve ¾ cup sauce. Pour remaining sauce over wings. Turn to coat with sauce mixture.
Cover slow cooker and cook on HIGH for 1 1/2 to 2 hours or LOW for 3 to 4 hours. Wings will not be completely cooked.
Heat broiler on HIGH. Turning and brushing with wings with reserved sauce, broil 10 to 15 minutes or until wings are browned and crispy.
In a medium saucepan over medium-high, melt butter. Add onion and garlic. Cook until onions are translucent, about 2 minutes. Add syrup, bourbon, ketchup, soy sauce, salt and black pepper. Cook until the sauce has reached a boil and is slightly thickened, 8 to 10 minutes
Reserve ¾ cup sauce. Pour remaining sauce over wings. Turn to coat with sauce mixture.
Cover slow cooker and cook on HIGH for 1 1/2 to 2 hours or LOW for 3 to 4 hours. Wings will not be completely cooked.
Heat broiler on HIGH. Turning and brushing with wings with reserved sauce, broil 10 to 15 minutes or until wings are browned and crispy.