Curry-Laced Tomato-Lentil Broth

Preparation : From "Classic Indian Vegetarian and Grain Cooking," by Julie Sahni (William Morrow). Wash lentils thoroughly. Place in a pot with 3 cups water and turmeric. Cook, partially covered, until very tender, about 30 minutes. Combine lentils and 1 cup water in a deep pot. Whisk to crush some of the lentils. Add the tomatoes, cumin, ground coriander, cayenne, onion, garlic and salt and bring to a boil. Lower heat and cook, partially covered, 10 minutes. Add lemon juice. Heat oil in a small skillet until hot. Add mustard seeds and cover so the seeds do not fly out of the pan. When they stop spattering, mix into soup. Stir in fresh coriander.