Place the frozen, boneless, skinless chicken breast in the crockpot. Add 2½ cups of Alfredo sauce.
Cover and cook on high for 6-8 hours, until fully cooked.
Tear or cut the chicken into pieces.
Add 1 cup Alfredo sauce, minced garlic, black pepper and refrigerated three cheese ravioli. Cover and cook on high for 15 minutes until tender and heated through. Add in whole milk if you need to spread the sauce out a bit more