Wash the onion, carrot, cabbage, celery, and bell pepper thoroughly and chop into bite-sized pieces.
Add olive oil to a pot and sauté the onion first.
Add the carrot, celery, bell pepper, and cabbage in order and continue to sauté.
Add the tomatoes (fresh or canned) and bring to a boil.
Pour in 500ml of water and season with salt and pepper.
Simmer on low heat for 40 minutes.