Add rice flour, urad dhal flour, jeera, salt and butter in a bowl and mix well.
Boil water, when it starts to boil switch off. Add water little by little.
Mix well and bring everything together to form a soft dough. First I used a ladle then mixed well with hands to bring it to a soft dough.
Now make cylindrical portion with the dough as shown below to fit in the murukku press.
Grease the murukku press and fill it up the prepared cylindrical dough. Grease a ladle with oil and keep it ready. Now press slowly in the form of a circle.
Heat oil in parallel, test by just pinching a tiny piece of batter, and adding it to oil. If it rises immediately then it is the correct stage. Then drop the murukku from the ladle into hot oil and fry them till golden brown in medium flame. Just give a tap the murukku will fall off into oil or just slide it.
Make sure it gets cooked evenly on both sides, turn over accordingly. Take it out when the color is golden brown on both the sides. You can even press the murukku directly in oil but I find it easier to press in ladle and then drop it in oil.
Drain in tissue, cool down completely and then store in airtight container. This type of murukku is very crispy and stays so longer, am sure you cant stop with one. Enjoy Thenkuzhal Murukku!