Step 1: Season the Chicken - Lay the chicken breasts in the bottom of your slow cooker. Sprinkle them evenly with salt, black pepper, garlic powder, and Italian seasoning. Do not rush this step. Seasoning early helps the chicken absorb flavor as it cooks.
Step 2: Add the Aromatics - Scatter the diced onion, minced garlic, and chopped sun dried tomatoes over the chicken. This is where the magic starts. As everything cooks, these flavors melt into the sauce and make the whole house smell amazing.
Step 3: Add Liquids and Cream Cheese - Pour the chicken broth into the slow cooker. Nestle the cream cheese cubes around the chicken. It will look a little odd at this stage, but trust the process. It all comes together later.
Step 4: Slow Cook - Cover and cook on Low for four to six hours or High for two to three hours. The chicken should be very tender and easy to shred or slice.
Step 5: Shred or Slice the Chicken - Remove the chicken from the slow cooker and set it aside. Whisk the sauce until the cream cheese is fully melted and smooth. Stir in the heavy cream and Parmesan cheese until creamy.
Step 6: Thicken the Sauce and Add Spinach - Mix the cornstarch and cold water in a small bowl, then stir it into the sauce. Add the spinach and cook on High for ten to fifteen minutes until the sauce thickens and the spinach wilts.
Step 7: Finish and Serve - Return the chicken to the slow cooker and spoon the sauce over the top. Sprinkle with fresh basil or parsley and serve warm.