Wash the dal well and add 3 cups of water. Add turmeric, hing and oil to the dal.
Pressure cook for 4 -5 whistles or till the lentil is cooked well. Drain the water to use in Rasam or Sambar.
Store the thick dal in an air tight container for a week.
Remove what is needed and quickly put it back. There is no need to freeze it if you want to use within a week.