To make dry rub, in a small bowl, stir together brown sugar, salt, pepper, garlic powder, onion powder, paprika, chili powder, cumin, and parsley.
Spray slow cooker with non-stick cooking spray. Add wings and pour over dry rub. Using your hands massage rub into chicken wings to coat evenly. (Using nitrile gloves is recommended.)
In the same bowl used for the dry rub, whisk together hot sauce, honey, and melted butter. Pour over wings and toss to coat.
Cover slow cooker and cook on high for 2 hours or on low for 3-4 hours, until internal temperature of wings reaches 165ºF.
Remove wings from slow cooker, placing them in a single layer on a large baking sheet. Set over rack on highest position and preheat for broiling.
Pour the remaining sauce from the slow cooker into a sauce pan. In a small bowl, whisk together cornstarch and water. Add to sauce, whisking to blend. Cook over medium-high heat until boiling, then reduce to medium-low, whisking often as it thickens, until it reaches a desired consistency, about 5 minutes.
Brush wings with sauce. Broil for 2 minutes. Remove from oven and brush once again with sauce. Broil for 2 more minutes. Wings should have a shiny, sticky coating of sauce once done. Repeat the process one more time if you would like a more caramelized consistency. Be careful not to bake too long or wings will become dry. Serve immediately and enjoy!