Heat olive oil in a large pot over medium heat. Add the chicken pieces and cook until golden on the outside. Remove and set aside.
In the same pot, add the diced onion and garlic. Sauté until the onion is soft and fragrant.
Stir in the sun-dried tomatoes, basil, oregano, and red pepper flakes. Cook for about 1 minute to release the flavors.
Pour in the chicken broth and bring to a gentle simmer. Let it cook for 10 minutes.
Lower the heat and stir in the heavy cream. Add the cooked chicken back to the pot and simmer for 10-15 minutes until the chicken is fully cooked and the soup thickens slightly.
(Optional) Stir in spinach or kale during the last 5 minutes of cooking.
Season with salt and pepper to taste. Ladle into bowls, garnish with grated Parmesan, and serve with crusty bread or garlic knots.