Wash and chop all vegetables: dice the onion, mince the garlic, slice the carrots and celery, chop the bell pepper and zucchini, and rinse the spinach.
In a large pot, heat olive oil over medium heat. Add diced onion and sauté for 3-4 minutes until translucent. Stir in minced garlic and cook for an additional minute.
Add sliced carrots, celery, and bell pepper. Cook for about 5 minutes, stirring occasionally.
Add diced zucchini, fresh spinach, canned tomatoes, vegetable broth, dried basil, and oregano. Season with salt and pepper. Bring to a boil, then reduce heat to a simmer.
Add tortellini and cook according to package instructions, usually about 5-7 minutes, until tender.
Taste and adjust seasoning if needed. Serve hot, garnished with grated Parmesan cheese if desired.