Homemade Rice flour is best for making Kai Murukku.
This also needs roasted urad dal, that is then ground to a powder.
Both the flours must be sieved to remove coarse powder.
Sieve and measure the finely powdered rice and urad dal and take it in a large mixing bowl. Add the remaining ingredients like soft butter, salt, asafoetida, jeera and hot oil and mix well until combined. When you gather the flour and press in your fist, it should form a ball as I have shown.
Sprinkle sufficient water and knead it into a smooth dough.
Place a plastic bottle cap in the center of a cloth (you could use parchment paper/plastic paper as well).
Grease your hand with oil and take a small portion of the dough. Roll it out using your index and thumb fingers and stick it to the cap. Then gently using a twist and turn motion, roll out the dough into the shape of murukku. This is in a clockwise direction, and you will have to make about three lines, ending at the same spot you began.
Continue with the rest of the dough and have some ready for deep frying.
Meanwhile heat oil in a kadai for frying. Once the oil is hot turn the flame to medium. Slide the murukku dough into the oil and fry until nicely golden.
Store it in an airtight container and enjoy.