Heat olive oil in a large Dutch oven or saucepot over medium-high heat. Add onions and basil, sauté until onions are tender and translucent. Add garlic, sauté for 30 seconds. Stir in tomato paste. Add flour, stir until dissolved about 1-2 minutes.

Add broth, tomatoes with juice, chicken, salt, and pepper to the pot; stir to combine.

Cover and simmer for 15-20 minutes (or until chicken is tender and no longer pink). Remove the chicken to a cutting board.

Add tortellini, spinach, Parmesan cheese and warmed cream (cream should be warmed because it may curdle if added cold); stir to combine.

On a cutting board, shred or cut the chicken into bite-size pieces. Add the chicken back into the pot; stir to combine.

Ladle soup into bowls and sprinkle with more grated Parmesan cheese and red pepper flakes if desired.