Sear the chicken in butter or olive oil for 2–3 minutes per side until golden.
Add rinsed rice to the bottom of a greased slow cooker. Place the seared chicken on top.
Whisk together broth, cream, Parmesan, sun-dried tomatoes, garlic, Italian seasoning, red pepper flakes, salt, and pepper. Pour over the chicken and rice.
Cook on LOW 4–5 hours or HIGH 2½–3 hours, until rice is tender and chicken is cooked through.
Stir in spinach 15–20 minutes before serving so it wilts gently.
Finish with fresh herbs and extra Parmesan.