Heat the oil in a large pot set over low heat.
Add the onion, garlic, turmeric, and cumin, and cook, stirring, until the onions are soft... about 10 minutes.
Add the carrots, potatoes, cauliflower, cabbage, tomatoes, broth, and 1 teaspoon salt.
Bring to a simmer and cook until the vegetables are tender, about 45 minutes.
Season to taste with salt and pepper, and serve.