Steps
1. Soak tamarind paste in 1 cup water and extract the juice.
2. Heat oil in a small pan, add mustard seeds, cumin seeds, dried red chili, and curry leaves; let them splutter.
3. Add chopped tomatoes, turmeric (optional), and cook until soft.
4. Add tamarind water, rasam powder, salt, black pepper, and asafoetida.
5. Bring to a boil and simmer for 5-7 minutes.
6. Garnish with chopped coriander leaves and serve hot.