Bring the 500 ml water to a boil in a pan.
Add the cumin seeds, both sesame seeds, salt and butter. Add the chilli powder and turmeric if using. Stir well and bring back to a boil.
Switch off the heat. Add the rice flour and mix roughly until the flour is incorporated. Cover for around 5 minutes, or until cool enough to handle.
Keep the dough covered with a moist cloth. Take one portion and knead it well before putting it into the chakuli maker.
Pipe spirals onto parchment paper squares, pressing the end gently against the spiral to secure it.
Heat the frying oil until medium-hot. Carefully lift each chakuli from the parchment and lower it into the oil, one at a time. Fry in batches, turning as needed, until cooked and the bubbling has almost stopped.
Lift out with a slotted spoon and drain on paper towels. Knead and pipe the next portion of dough, keeping the remaining dough covered.
Let the chakulis cool completely before storing in an airtight dabba.