Heat the olive oil in a large pot over medium heat, then add the chopped onion and cook for 4 to 5 minutes until soft and translucent.
Stir in the minced garlic and cook for about 30 seconds, taking care not to let it brown.
Add the crushed tomatoes, vegetable broth, oregano, dried basil, salt, and black pepper, then stir everything together.
Bring the soup to a gentle boil, reduce the heat, cover the pot, and simmer for about 15 minutes.
Carefully blend the soup with an immersion blender until smooth, or leave a few tomato pieces for a more rustic texture.
Stir in the low-fat milk and fresh basil, then warm the soup over low heat for another 2 to 3 minutes without boiling.
Taste, adjust the seasonings if needed, and serve warm with extra basil on top.
