Boil water in a thick bottomed vessel / saucepan. Add salt, jeera and ghee. When water (1 1/2 to 1 3/4 cups - not more than 1 3/4 cups) starts boiling add rice flour and mix well. Rice flour should be well mixed with water. Stir continuously. Keep aside for 15 minutes.
Add 1 tsp oil to the rice dough and knead well. Divide into 6 - 7 lemon sized portions.
Dilute red chilli powder, pepper powder, coriander powder and turmeric powder in 1 tbsp water and keep it ready (spice mix).
Heat oil in a pan. Add finely sliced onion and fry till golden colour on a medium to low heat.
Add curry leaves and fry well.
Add chopped garlic and fry well until light golden colour.
Add diluted spice mix and stir well on a low heat for 2 - 3 minutes until thickens / water dries up / raw smell goes.
At this stage, add marinated prawns, cover again (do not add water) and cook on a medium heat for 5 minutes or until done and prawns tender (light pink in colour). Overcooking will make the prawns hard in texture. Switch off the heat and stir well.
Clean banana leaf. Smoke this leaf on flame for a few seconds so that it becomes flexible and easy to fold.
Cut banana leaf into 7 - inch square pieces.
Take a piece of banana leaf.
Keep a lemon sized rice dough portion over it.
Keep another piece of banana leaf smeared with oil (with oiled portion facing down) the dough.
Press evenly to form a thin circle of rice dough of approximately 10 - 12 cm diameter.
Carefully remove the leaf on top.
Now one will see a thin circle of rice dough.
Keep 4 tsps prawns curry mixture in it length wise along its centre.
Fold into semi-circle and seal the edges tightly - such that the outer covering is the banana leaf which was placed initially.
Repeat this process for the remaining dough / filling.