For cooking the lentils in a pot - rinse and soak the lentils for atleast an hour. boil 3-4 cups water with a pinch of turmeric. add the drained lentils. whilst cooking remove the scum with a spoon. cook the lentils till the each lentils has become soft and mushy. add more hot water if required while cooking. once the lentils are cooked, you can the tomatoes, etc and simmer till the tomatoes are cooked and then proceed with the recipe.