Heat the olive oil and butter in a large pot or Dutch oven over medium heat. Add the onion, carrots, and celery, and cook for 5 to 7 minutes, stirring occasionally, until softened.

Add the garlic and cook for 30 seconds, just until fragrant. Stir in the flour and cook for 1 minute to form a light roux.

Slowly pour in the chicken broth while stirring to prevent lumps. Add the chicken, diced tomatoes, sun-dried tomatoes, Italian seasoning, red pepper flakes, salt, and black pepper.

Bring the soup to a gentle boil, then reduce the heat to low, cover, and simmer for 15 to 20 minutes, or until the chicken is cooked through.

Remove the chicken from the pot and shred it with two forks. Return the shredded chicken to the soup.

Stir in the pasta and cook uncovered according to package directions, stirring occasionally, until tender.

Reduce the heat to low and stir in the heavy cream, spinach, Parmesan cheese, and fresh basil. Cook for 2 to 3 minutes until the spinach wilts and the soup is creamy.

Taste and adjust seasoning with additional salt and pepper if needed. Serve warm with extra Parmesan and basil if desired.