Pressure cook the dal with garlic, turmeric, hing and a teaspoon of oil and two cups of water and pressure cook for two whistles.
Remove and drain the dal and mash it. Preserve the water.Heat remaining oil in a non-stick deep pan.
Add urad dal, mustard seeds and fenugreek seeds and saute for a minute.
Add onions, tomatoes, green chillies and saute till the tomatoes get cooked.
Add salt and the dal water and bring it to boil. Add the dal and cook for two to three minutes.
Add curry leaves and coriander leaves and mix well.Serve hot.