It's a easy recip. Grind tomato, pepper, jeera, curry leaves, turmeric, garlic and asafoetida together. Add the grinded mixture into water and salt. Now the rasam water is ready. In a kadai heat oil, add mustard seeds and urad dal and add dry red chilli after that add the rasam water and boil until the water gets rolling. Switchoff and garnish with cofiander leaves.