Season the chicken with Cajun seasoning, smoked paprika, garlic powder, onion powder, and black pepper.
Place the chicken in the crockpot.
Add the butter, garlic, chicken broth, and sun-dried tomatoes.
Cover and cook on LOW for 5 to 6 hours or HIGH for 2½ to 3½ hours, until the chicken is tender.
Remove the chicken to a plate.
Stir the heavy cream and Parmesan cheese into the sauce.
Mix the cornstarch and cold water until smooth, then stir it into the crockpot.
Cook on HIGH for 15 to 20 minutes until the sauce thickens.
Return the chicken to the crockpot and coat it in the creamy Cajun butter sauce.
Garnish with fresh parsley and serve over cooked rice.