Heat the olive oil in a large pot over medium heat. Add the onion, celery, carrots, and garlic and sauté for 5 minutes, stirring occasionally.
Add the diced tomatoes, vegetable broth, oregano, basil, thyme, salt, and pepper. Bring to a boil, then reduce the heat to low and simmer for 45 minutes.
Remove from heat and let cool for 10 minutes. Carefully blend the soup in batches until smooth and creamy.
Serve hot with your favorite toppings. Enjoy!