Soak the puffed rice in enough water separately for 1/2 hour
Grind the rice in the grinder with a little water to get coarse consistency and at this stage add the puffed rice and grind further till the batter is very smooth adding more water if necessary. The batter should be runnier than idli batter but thicker than dosai batter.
Let it ferment for 7-8 hours
Just before making the uthappam add the baking soda
Heat a small deep kadai in moderate heat. Add a tsp of oil, then pour a ladle of batter, drizzle oil around it and few drops on the top
Cook for 2-3 minutes keeping the pan covered. Should be cooked only on one side.
The center gets puffed up very well and the uthappam turns a little pale.