To make puran poli
Soak chana dal in water for 5-6 hrs (better to cook it in a pressure cooker). Put it in a large greased frying pan & add jaggery (almost 1/2 quantity of dal).
Stir well heating on medium flame till water is evaporated.
Let it cool.
Make wheat + maida dough & make small balls. Flatten the ball and add little of above chana dal mixture & close ends of dough. Flatten them slowly by using roller. Fry them on flat cookware (tawa) into rotis.