Preheat oven to 350 F. Combine carrots and potatoes in saucepan. Cover with water and bring to a boil. Add salt and simmer, covered, about 10 minutes or until vegetables are tender. Drain well; reserve cooking liquid for soups.
Add cauliflower to a saucepan of enough boiling salted water to cover florets by about 1 inch and boil, uncovered, over high heat for 2 minutes. Add green beans (if using) and boil for two minutes. Add zucchini and boil for one minute or until vegetables are crisp tender. Drain in colander, reserving cooking liquid. Rinse vegetables with cold water and drain well.
Heat oil in a large ovenproof stew pan or saute pan. Add onion and saute over medium heat, stirring often, for 10 minutes or until golden brown. Add garlic, ginger, chilis, paprika, cayenne, cinnamon, cloves, turmeric, nutmeg to taste, and cumin (if using) and cook over low heat, stirring for one minute. Remove from heat. Stir in tomato paste (if using) and 2 tablespoons water. Mix with vegetables. Taste and adjust seasoning. Leave mixture in stew pan or transfer it to a 2-quart casserole dish.
Cover and bake for 20 minutes or until heated through and vegetables are tender enough for your taste. Serve hot.
Makes four servings.