Boil urad dal in a pressure cooker with 2 cups of water.
Allow it to cool completely. Then mash it well or run it through a food processor to create a smooth paste. Do not add any water.
Add rice flour, salt, cumin seeds, hing, sesame seeds, and the softened butter.
Adding a little water a time mix everything together to form a soft dough.
Gather 6 small saucers or squares of aluminum foil and lay them out on the counter.
Heat the oil in a large kadai or deep saucepan until the oil begins to shimmer. The oil is ready when a little bit of dough dropped in releases air bubbles and rises to the surface quickly. Be careful not to overheat the oil.
Fit the star plate into the chakli press and spray some non stick spray or lightly oil the container of the press. Load a ball of dough into the press and make spiral shapes on each saucer. Flip the chakli from each saucer onto a wide slotted spoon and lower gently into the oil. Fry in batches of 6 being careful to cook on a medium fire so as to cook the chakli through.
Drain on paper towels until the chakli is completely cooled and then store in an airtight container for up to a month.