2tbspsunflower or any other flavourless oil +1 tbsp for tempering
1tspskinless black gram lentilsthey are white without skin
For the spice mix
6dried red chillies
1.5inchlong cinnamon stick
Steam or parboil the potatoes till they are about half done. Drain well and peel.
While the potatoes boil, make the spice mix or masala. Heat a pan or griddle on low heat and roast the spices (except the turmeric powder) individually for a few minutes (if you roast them together, some, like the dried chillies may roast quicker and burn), cool and dry grind with the turmeric to a coarse spice powder.
Preheat the oven to 180 degrees C. Arrange the potatoes on a baking tray, sprinkle with salt and drizzle with 2 tablespoons of sunflower oil. Shake tray to coat all the potatoes and bake in the centre of the oven for 30 minutes. Then crank up the heat to 200 degrees C and move the tray to the top rack under the broiler, tossing the potatoes every now and then to ensure a crisp, even browning.
Remove from the oven and sprinkle generously with the spice mix to coat evenly. Heat one tablespoon oil in a small pan till very hot, toss in the mustard, cumin and black lentils so that they splutter, turn off the heat and add the curry leaves. Pour the tempering over the potatoes and check the seasoning. Return to the oven for 5 minutes at 180 degrees C, to heat it through. Serve with dal and rice or chapatis.