Roast Sooji (Rava) in a Kadai with Ghee and keep it aside. Take one and half cup of Sour Curd/buttermilk. If you are taking Sour Curd make sure that you mash all the lumps. Now add the Roasted Sooji (Rava), Cumin Seeds, Pepper Powder and Salt and mix it as a batter. Leave it aside. If the Curd/Buttermilk that you added is really Sour, then it is enough if you let it aside for 10-15 minutes. If it is not Sour, then let the batter aside for 45 mts to 1 hr. Use Idly Cooker and steam cook this batter as Idlis.