Finely chop the onion, celery and garlic.
Peel the sweet potatoes, then cut them into bite-sized chunks.
Roughly chop the carrot and red pepper.
In a large, heavy-based pot, heat the oil, then gently sauté the onion and celery for 5 minutes until soft, then add the garlic, carrot, pepper and sweet potato pieces.
Add the oregano, then gently sauté the vegetables over low heat for about 5 minutes.
Stir in the tomato purée.
After a minute, add the vegetable stock and passata, bring to the boil, then add the pasta and beans.
Simmer, uncovered, for 10 minutes.
When the veggies are tender, add the kale and cook for another 3-5 minutes.
Stir in the parsley.
Taste the soup and season to your liking.
Serve warm.