Pressure cook the lentils with turmeric, chillies, water and salt till nicely mashed - around 5-6 whistles. Allow to the pressure to go off completely.
Grind the ingredients under "for grinding" till coarse and without any bites.
Open the pressure cooker lid and add the ground mixture. Give it a good mix.
Keep on low flame on simmer for five minutes, with a closed lid. Switch off.
Heat oil in a small pan. Splutter the mustard seeds. Briefly fry the red chillies and curry leaves and pour into the prepared lentils.
Serve hot as side for ghee rice and chicken/beef curry.