Chop the onion, dice the carrots and celery, and mince the garlic. Set aside.

Heat olive oil in a large Dutch oven or heavy-bottomed pot over medium-high heat. Add the ground turkey and cook, breaking it up with a spoon, until fully browned. Drain any excess fat.

Add the chopped onion, carrots, and celery to the pot with the browned turkey. Cook, stirring occasionally, for 5-7 minutes, or until the vegetables have softened. Add the minced garlic, dried oregano, dried basil, and red pepper flakes (if using), and cook for another minute until fragrant.

Pour in the crushed tomatoes and chicken broth. Stir everything together. Bring the mixture to a boil, then reduce the heat to medium-low, cover, and let it simmer for 10-15 minutes to allow the flavors to meld.

Stir in the uncooked orzo pasta. Continue to simmer, uncovered, for another 8-10 minutes, or until the orzo is al dente and the soup has thickened slightly. Stir occasionally to prevent the orzo from sticking to the bottom of the pot.

Taste the soup and season with salt and freshly ground black pepper as needed. Ladle the hot soup into bowls. Garnish each serving with fresh chopped parsley and a sprinkle of grated Parmesan cheese, if desired.