Heat olive oil in a large pot over medium heat. Add diced onion and cook until softened, about 3-5 minutes. Stir in minced garlic and cook for another minute until fragrant.

Pour in the crushed tomatoes and vegetable broth. Bring the mixture to a gentle simmer.

Add the orzo pasta to the simmering soup. Cook for 8-10 minutes, or until the orzo is tender, stirring occasionally to prevent it from sticking to the bottom of the pot.

Season the soup with salt and pepper to taste. Ladle into bowls, garnish with fresh basil if desired, and serve hot.