Begin by heating the olive oil in a large, heavy-bottomed pot over medium heat. Once hot, add the finely diced onion and sauté for 4-5 minutes, or until it becomes translucent and tender.
Next, add the minced garlic to the pot and continue cooking for an additional minute, stirring frequently until the garlic is fragrant and lightly golden.
Incorporate the diced carrots, celery, and bell pepper into the pot. Sauté the mixture for 5-7 minutes, stirring occasionally, until the vegetables have softened.
After the initial vegetables have softened, stir in the diced zucchini and let it cook for another 3 minutes.
Pour in the canned diced tomatoes along with their juices and the vegetable broth. Stir the contents to ensure everything is well combined.
Season the soup with dried thyme, dried basil, and salt and pepper to taste. Bring the mixture to a gentle boil, allowing the flavors to meld.
Once the soup reaches a boil, add the orzo pasta, reduce the heat to a low simmer, and cook for approximately 10 minutes, or until the orzo is al dente. Be sure to stir occasionally to prevent sticking.
In the final two minutes of cooking, fold in the fresh spinach and the juice of the lemon, letting the spinach wilt and brighten the flavors of the soup.
Before serving, taste the soup and adjust the seasoning if necessary, adding more salt, pepper, or lemon juice if desired.
Ladle the soup into bowls and garnish each serving with a sprinkle of freshly chopped parsley for a burst of color and flavor.
Notes
Feel free to customize the vegetables based on your preference.