Make a dough using maida just like chappati dough. But this should be a bit elastic in texture. Rub the dough with gingely oil and cover it with a muslin cloth and set aside for a while. In the mean time make the Pooranam.
Pressure cook Bengal Gram Dal. Let it cool. Grind it along with cardamom powder. Make a syrup of Jaggery using 1/2 cup of water and when it boils add grated coconut and bring it to a boil in medium flame. Add the ground bengal gram and mix well. Saute well till all the jaggery is absorbed and it becomes thick. Remove and let it cool.
Make thin chappatis from the dough. Make a ball of big gooseberry size of the bengal gram mixture. Place it in the middle of the chappati. Pull the sides of the chappati and cover the pooranam thoroughly. Flatten it again. Heat a tawa and put the poli. Pour a tbsp of oil around it to help in cooking. Ensure both the sides are golden brown in colour. Remove from the tawa and spread ghee on both the sides. Serve hot.
Note: The Poli will come out well and will also taste very good if the outer cover dough is let to set for atleast 2 to 3 hours the best result can be obtained when it is let to set for about 6 hours.