Begin by spraying the slow cooker insert with cooking spray to prevent sticking. Place about 2 pounds of boneless skinless chicken breasts inside, ensuring even spacing. Season generously with salt and freshly ground black pepper.

In a mixing bowl, whisk together 1 cup of heavy cream, 1 cup of chicken broth, and ¾ cup of grated Parmesan cheese until smooth. Then, add 2 tablespoons of cornstarch, 1 tablespoon of Dijon mustard, 2 teaspoons of Italian seasoning, ½ teaspoon of smoked paprika, and 2 cloves of freshly minced garlic.

Pour the creamy sauce mixture evenly over the chicken in the slow cooker. Sprinkle in ½ cup of drained and diced sun-dried tomatoes.

Cover the slow cooker and set it to cook on LOW for 4 to 5 hours or on HIGH for 2 to 3 hours.

In the last 10 minutes of cooking, remove the lid and stir in about 2 cups of fresh baby spinach.

Once cooking time is complete, taste the sauce and adjust seasoning with additional salt or pepper as necessary. Serve immediately over pasta or your preferred side.