In a small bowl, mix salt, pepper, Italian seasoning, garlic powder, and garlic salt. Using half of the seasoning mixture, season both sides of the chicken breasts with the mixture. Set the rest of the seasonings aside.
Combine the water and bouillon cube and put it in the microwave for 4 minutes. When it is done, stir it well and set it aside.
In a large skillet over medium high heat, add the olive oil and chicken breasts. Let the chicken breasts cook for 5 minutes per side, or until browned.
Cover the skillet and turn the heat to medium-low. Allow the chicken breasts to cook until they are no longer pink in the middle. Depending on how thick your chicken breasts are, this may take 3 to 5 additional minutes.
Remove the chicken from the skillet and set it aside. Add butter, onions, sun-dried tomatoes and garlic to the skillet. Mix well and cook for 1 to 2 minutes over medium heat.
Add water and the chicken bouillon cube mixture and stir well. Deglaze the bottom of the pan by using your spatula to gently scrape the bottom of the pan to get all browned bits up and into the sauce.
Add the remaining seasoning mixture and stir well. Allow the pan to simmer for 2 to 3 minutes.
Add the heavy cream and parmesan cheese and stir well to combine. When the pan starts to gently bubble, add the spinach and stir.
Turn the heat to low and add the chicken breasts back into the skillet. Cover and let simmer for 2 to 3 minutes.
Spoon the sauce over the top of the chicken and serve.