Pressure cook the black grams with salt and four cups water till done. Remove and mash the dal mixture.
Heat oil in non stick pan add onions and saute till light brown. Add tomatoes, ginger, garlic, fenugreek, salt, red chilli powder, chaat masal, cumin powder and saute for two minutes.
Add the dal mixture and half cup water and let it simmer for five minutes.
Add garam masala powder and cream and cook for a minute
Serve hot with rotis.