Season the chicken. Pat the chicken dry and sprinkle both sides with salt, pepper, and Italian seasoning. If you like heat, add a pinch of red pepper flakes.
Optional sear for extra flavor. In a skillet, warm olive oil or butter over medium-high heat and sear the chicken 2–3 minutes per side. This step adds flavor but isn’t required.
Build the base in the crockpot. Add chicken broth, minced garlic, and sun-dried tomatoes to the slow cooker.
Stir to combine.
Add the chicken. Place the chicken into the liquid mixture in an even layer.
Cook low and slow. Cover and cook on Low for 3.5–4.5 hours or on High for 2–3 hours, until the chicken is cooked through and tender. Avoid lifting the lid too often.
Make it creamy. Whisk the cream cheese with a few tablespoons of hot cooking liquid until smooth, then stir it back into the crockpot. Add heavy cream and Parmesan.
Stir well to melt and combine.
Add the greens. Stir in the spinach and let it wilt for 5–10 minutes on Low. Taste and adjust salt, pepper, and red pepper flakes. Add lemon juice if you like a brighter finish.
Shred or slice the chicken. For a saucier dish that clings to pasta or rice, shred the chicken in the crockpot.
For a neater presentation, slice or serve whole pieces and spoon the sauce over the top.
Serve and garnish. Spoon over pasta, rice, or mashed potatoes. Finish with fresh basil or parsley and extra Parmesan.