Slice the cabbage quarters into thin strips across the leaves. Heat the oil in a large saucepan. Add the cabbage, carrots, celery and parsnips and cook 10 to 15 minutes over medium heat, stirring frequently.
Stir the stock into vegetables and bring to a boil. Skim off any foam that rises to the top. Add the potatoes, cauliflower and tomatoes with the herbs, and salt & pepper to taste.
Bring to a boil. Reduce the heat to low, cover the pan, and simmer until vegetables are tender, 15-20 minutes.