Pressure cook the dal in 1 1/2 cups water for 4-5 whistles. Whisk and keep aside. Heat oil in a pan and temper with mustard seeds and fenugreek seeds. After it stops spluttering, add the onion, ginger, garlic, green chilies and curry leaves.
Saute till light brown in colour. Add the chopped methi leaves and continue to fry on low flame for 10 minutes or till and leaves are completely wilted and dry.
Add the boiled dal, salt, turmeric powder, tamarind paste, red chili powder and sambar powder. Simmer for 3-5 minutes. Serve with chapatti or plain steamed rice.