Heat olive oil in a large pot over medium heat. Add finely chopped onion and pinch of salt, cooking for about 8 minutes until soft and golden. Stir in minced garlic for an additional 15-20 seconds until fragrant.

Pour in pureed tomatoes and broth, stirring well to combine. Add dried basil, oregano, salt, black pepper, and red pepper flakes. Bring to a boil, stirring occasionally.

Once boiling, add tortellini and shredded chicken. Reduce heat to simmer and cook for about 10 minutes until tortellini is al dente. Stir occasionally.

Stir in fresh spinach, crumbled feta, and heavy cream. Continue to simmer for 5 minutes until spinach has wilted and soup thickens slightly.