Pick, rinse and soak sabut urad dal or whole black gram in plenty of water overnight.
Puree 3 large tomatoes with cashews if using.
To make maa di dal heat 3 tablespoons oil or ghee in a pressure cooker base.
Once the oil is hot temper with cumin leaves and a bay leaf.
Add sliced onions and saute till they turn soft.
Next add minced ginger garlic and slit green chilies. Saute till the raw smell goes off.
Add pureed tomatoes and mix. Add all the spice powders and saute till tomatoes release fat from the sides.
Now add the soaked and drained sabut urad dal. Mix well and add required water and salt. Cover and pressure cook for 30-40 minutes (Around 20-22 whistles)
Once the pressure settles check if the kali dal is creamy and completely cooked. Simmer for 5-6 minutes to adjust consistency. Add cilantro leaves and mix well. Serve maa di dal hot.