Spray a 4-quart slow cooker with cooking spray; set aside.
In a large mixing bowl, whisk together pudding mix, corn muffin mix, and 3 cups of milk until thickened, about 2 to 3 minutes; set aside.
In a medium mixing bowl, whisk together remaining ingredients. Stir into pudding mixture until well combined. Transfer to slow cooker. Cover and cook on high for 1 hour. Turn slow cooker to low and stir. Cover and continue cooking for 1 more hour. Stir, cover and cook for 1 hour more.