In a large, heavy-bottomed pot, pour in the olive oil and place it over medium heat. Once heated, add the Italian sausage. Cook for approximately 5-7 minutes, using a wooden spoon to break up the sausage into bite-sized pieces. Ensure the meat is browned evenly.
Once the sausage is cooked through, add the diced onion, carrots, and celery to the pot. Sauté these vegetables for another 5-7 minutes until they are tender and the onion is translucent.
Incorporate the minced garlic into the mixture and sauté for an additional minute, just until you can smell its aromatic warmth.
Pour the chicken broth into the pot along with the undrained diced tomatoes, dried basil, and dried oregano. Season the mixture with salt and freshly ground black pepper, and bring the soup to a gentle simmer.
Allow the soup to simmer for about 10 minutes. This not only infuses the flavors but also helps the vegetables soften further.
Add the tortellini to the pot and cook according to package instructions, which should take around 3-5 minutes until they are tender.
In the final minute of cooking, stir in the fresh spinach, gently folding it into the soup until it wilts and brightens the dish.
Taste the soup and adjust the seasoning with more salt or pepper if needed.
Notes
Ladle the soup into deep bowls and top with grated Parmesan cheese and fresh spinach leaves. Serve with crusty bread.