Pat the chicken breasts dry with paper towels to help them cook more evenly in the slow cooker. In a small bowl, combine the salt, Italian seasoning, paprika, and black pepper. Rub this seasoning mixture all over both sides of the chicken breasts, then place them in the slow cooker.

In a separate bowl, whisk together the heavy cream and cornstarch until smooth—the cornstarch prevents the sauce from breaking during the long cooking time. Stir in the minced garlic, salt, and black pepper, then fold in the chopped sun-dried tomatoes and grated Parmesan cheese. I like using Sartori cheese here because it melts beautifully and adds a richer flavor than standard Parmesan. Pour this entire sauce mixture over the seasoned chicken in the slow cooker.

Cover the slow cooker and cook on low for 3 hours, or until the chicken reaches an internal temperature of 165°F when checked with a meat thermometer at the thickest part. Do not lift the lid during cooking, as this lets heat escape and extends the cooking time unnecessarily. I find that checking the temperature after 2.5 hours helps ensure you don't overcook the chicken.

Once the chicken reaches 165°F, stir the fresh spinach into the creamy sauce around and over the chicken. The residual heat will gently wilt the spinach in about 1-2 minutes. Taste the dish and adjust seasoning with additional salt, pepper, or Italian seasoning as needed.