Wash and soak the rice in sufficient water for about 4-5 hours. Drain , set aside.
In your mixer/grinder, add the drained rice, grind using little toddy (I used about 1 & 1/4 cup) to a smooth batter. Add the toddy in increments so that the batter grinds well. Remove about 1 & 3/4 cup batter in another large bowl. Transfer the remaining batter to another mixing bowl (you will have about 1 & 1/2 cup batter).
Grind the freshly grated coconut with about 2-3 tablespoons of toddy. Set aside.
Mix coconut and grated jaggery in a bowl. Cook this mixture on low heat until all the moisture has evaporated and the mixture has dried up.
For plain sannas-To one bowl with the rice batter, add coconut batter [prepared in step 3, 1/4 cup sugar and about 1/4 teaspoon salt. Add more toddy if required to adjust the batter consistency.
For sweet sannas-To the other bowl of rice batter, add 1/4 cup sugar and 1/4 teaspoon salt.
Cover, leave it a warm place to ferment and double in size for about 4-6 hours.
Grease the sanna moulds with little oil.
For plain sannas, fill the moulds to about 3/4 th with the sanna batter.
For sweet sannas, fill the moulds to 1/4th with sanna batter, then add a generous amount of the coconut-jaggery mix, fill with more sanna batter up to 3/4th of the mould.
Steam for about 20-25 minutes.
Transfer to a serving platter, serve plain sannas with gravy of your choice or eat it as is. It's delicious on its own. The sweet jaggery sannas are great with your morning cuppa or evening chai.