Cut cabbage, onion, carrot, bell pepper, celery, and tomato into bite-sized pieces.
Heat olive oil in a pot and sauté onion and celery.
Add all the remaining vegetables and stir-fry for 2-3 minutes.
Add 500ml of water and tomato purée, then bring to a boil.
Reduce to low heat and simmer for 20–30 minutes until the vegetables are tender.
Season with salt and pepper to finish.