Heat olive oil in large pot over medium heat.
Add diced onion and cook until softened completely.
Stir in chopped carrots and sliced celery pieces.
Cook vegetables for five minutes until slightly tender.
Add minced garlic and cook for one minute.
Pour in diced tomatoes with their juices carefully.
Add vegetable broth and bring mixture to boil.
Reduce heat and let soup simmer for minutes.
Add small pasta and cook until tender.
Stir in drained cannellini beans and fresh spinach.
Season with oregano, salt, and black pepper.
Simmer for two more minutes until heated through.
Garnish with fresh basil leaves before serving hot.