In a pan, heat the oil on medium heat until its nice an hot.
Add mustard seeds and after a few seconds of sputtering, add cumin and coriander seeds.
Add in the asofetida(hing) and curry leaves and mix.
Add in the red chili and garlic and cook till garlic is golden brown.
Add in tomatoes and cook for a minute.
Rinse the soaked daal and add it to the pan with the water, salt and turmeric.
Mix well. Cook covered for 10-15 minutes.
Add in the butter and take off heat!
Serve hot garnished with cilantro and lime wedges !. The Daal goes well with basmati rice or as a side dish with Roti and and any dry vegetable stir fry.
Notes
Variations: can use other split daals like toor, masoor(pink), individually or in combination. Add in onions and or tomatoes to the tempering. Add in spices like fennel seeds or bay leaves to the tempering.