Wash the dal and soak it in hot water for 30 minutes. After that put it in a pressure cooker with 1 and a half cups of water, turmeric powder and salt and boil it for 1 whistle or 10 minutes.
While the dal is boiling, peel the radish and cut the radish in 2 mm thickness circles. Then stack the circles and cut them into long strips, like potato sticks. If you find this cumbersome, you can cut the radish into quarters. Keep the radish in a bowl of water till the dal is ready to be cooked.
Once the dal has boiled, open the pressure cooker and keep it aside. If the dal is still holding shape and is a bit tough, don't worry, it will cook further.
In a kadai, take 1 tbsp of ghee and add 2 dried red chilies when the ghee is hot. Add the nigella seeds. Rub the nigella seeds between your fingers before adding to the oil for greater flavour.
Now discard the water from the radish and add the radish strips to the kadai.
On high heat, stir fry the radish. Sprinkle a little bit of salt to help in the cooking process. After a couple of minutes, you can cover and let the radish soften. It doesn't take long if you have cut them into sticks.
Once the radish has cooked, add the dal to this along with the water from boiling. Keep the heat at high and let the dal boil.
With the back of your ladle, mash the bottom to get a nice thick consistency.
Add sugar and check to season. Finally, add ghee and plenty of split green chilies.
Turn off the heat and serve motor dal with steamed rice.