Pappadum is an Indian preparation, available in most Indian stores. It is a thin wafer liker preparation that can be made with rice, black gram flours also. It is generally deep fried but also can be micro waved. I had some tapioca growing in my back yard, but it may also work with ready to use tapioca flour available in market. The tapioca is to be cut, cleaned and chopped into small pieces. After letting it dry in the sun for couple of days. I get it ground in a mill. I l would like to give a word of caution. I discard the initial lot say 1-2 kg, to ensure it is gluten free. I do the same with rice flour. My uses the discarded portion for her rangolis. It is a popular art form using white powder and colors to make beautiful colored sand like paintings. Talk of resource management.Whew! For 5 cups of the flour I use 10 cups of water. Bring the water to boil, add salt, chili powder, and asafetida. Add the flour to this and ensure no lumps are formed. Cook till the dough has a shiny feel. Add sesame seeds (til) to this. Spread out plastic sheets. Make a ball of the dough when still medium hot. Keep a bowl of water. Dip your hands in the water, and spread out the dough on the plastic sheet with your hand, into a round shape. The water is used so that the dough does not stick to your hands. Let dry in the hot sun for 2-3 days. One can also add finely chopped onion to the dough; shaped into dumplings .Leave those to dry. The photo showas the papads left to dry in the sun. Also refer ,My first GFCF cookie post, where again I have used tapioca flour.