Wash and soak aval in hot water for 20 mins. Water should be just enough to immerse the aval. Keep covered.
After 20 mins, all the water will be absorbed by the aval.
Take the soaked aval in mixie. Grind it with melted butter.
Make sure to grind really smooth by wiping down the sides several times in between grinding. It should be smooth.
Transfer the ground aval paste to a mixing bowl.
Add rice flour, ajwain, cumin seeds, salt, asafoetida and make a smooth soft dough. No need for water. Refer notes.
Take a murukku press with small hole plate and fill it with prepared dough.
Heat enough oil in a kadai. Grease several flat ladles and squeeze murukku over it.
Transfer the squeezed murukku into hot oil.
Once bubbles reduce in one side, flip and cook the other side in medium flame.
Wait until bubble ceases and drain over paper towel. Repeat to finish.