- Heat olive oil in a large saucepan, over medium heat.
- Add leek, carrots, zucchini, green beans and celery.
- Cover, and reduce heat to low.
- Cook for 15 minutes, shaking the pan occasionally.
- Stir in the stock, tomatoes and thyme.
- Bring to a boil, then replace the lid, and reduce heat to low; simmer gently for 30 minutes.
- Stir in the cannellini beans with liquid and pasta.
- Simmer for an additional 10 minutes, or until pasta is al dente.
- Season with salt and pepper to taste before serving.