Add chicken to the crock pot. Top the chicken with the butter, minced garlic and salt.
Cover and cook on low for 5-7 hours or on high for 2.5-3.5 hours until the chicken has an internal temperature of 165 degrees F.
After this time, remove the chicken. Then stir together the cornstarch, heavy whipping cream and grated parmesan cheese in a small bowl.
Whisk this mixture into the sauce in the crock pot, stir the spinach into the sauce and place the chicken back on top.
Cover and cook on low for 30 minutes to thicken and heat the sauce through and the spinach is slightly wilted.
Serve warm as is or over pasta and enjoy!
Notes
*You can brown the chicken in a large skillet with olive oil before adding it to the crock pot if you prefer. *Make sure to use grated parmesan cheese not shredded as the shredded does not melt as evenly in the sauce. *Store leftovers in an airtight container in the refrigerator for up to 5 days.