Pat the chicken breasts dry and season with salt and pepper.
Place the chicken in the bottom of the crockpot.
In a small bowl, mix paprika, onion powder, cayenne pepper, thyme, oregano, salt, and black pepper to make the Cajun seasoning.
In a large bowl, melt butter with olive oil. Add minced garlic and mix well.
Brush the garlic-butter mixture over the chicken.
Pour chicken broth over the chicken and sprinkle the Cajun seasoning evenly.
Cover and cook on low for 6-7 hours or high for 3-4 hours.
In a small bowl, whisk cornstarch with a splash of water to make a slurry. Add heavy cream and stir well.
Once the chicken is tender, turn the crockpot to high (or remove the chicken and set aside).
Pour the slurry into the sauce and stir well. Continue cooking for 15-20 minutes, until the sauce thickens and becomes glossy.
Shred the chicken with two forks and stir into the sauce until well combined.
Serve over warm cooked white rice, garnished with fresh parsley.