Preheat your oven to 400ºF. In a medium bowl, combine the spinach, cream cheese, and heavy cream. To the same bowl add in half the garlic, the salt, onion powder, cayenne pepper, black pepper, Italian seasoning, parmesan cheese, 1/2 of the mozzarella cheese and combine well. Lay the chicken flat in the bottom of a large baking dish. Season the chicken breasts with salt, pepper and the remaining half of the garlic. Spread the spinach and cream cheese mixture on top of the chicken, and top with the sun-dried tomatoes. Sprinkle the remaining mozzarella on top and cover with foil. Put it in the oven and bake for about 20 minutes. Remove the foil and bake for an additional 15 minutes, or until chicken is cooked through. Remove from the oven and let rest for 5 minutes. Sprinkle with chopped parsley or rosemary and serve.