1. Heat oil over medium-high heat in a stock pot with a tight-fitting lid. Add cabbage, cauliflower, leek, onion, carrot and celery and stir to coat them with oil.
2. Cover, reduce heat to medium-low and cook gently until vegetables release their juices, about 10 minutes. Stir occasionally.
3. Add tomatoes with their liquid, broth, potato and thyme.
4. Increase heat to medium-high until liquid boils, then cover, reduce heat, and simmer soup for 10 minutes.
5. Add Swiss chard and simmer for 10 minutes. Remove from heat.
6. Add parsley and season with salt and pepper. Let sit for 10 minutes before serving.
7. Serves 6.

VARIATIONS (not included in nutritional analysis)
Garnish with fresh dill, or a sprinkling of grated parmesan cheese. Add ½ cup canned beans per serving.