Measure the rice flour in a bowl and add the salt required. Mix it well.
Meantime, heat water in the pan and let it come to a boil. Add 1/2 tbsp of oil (either coconut oil or gingelly oil).
Add the rice flour slowly and start stirring the mixture. The dough will start to come together very quickly. Make sure you try to make it without any lumps. Once the dough starts leaving the sides of the pan and forms a ball, turn off the flame and the cover the pan.
Let the dough rest until it is warm enough to handle. Covering the pan also lets the flour cook further and prevents it from drying out. If your lid is not airtight, cover the dough with a wet kitchen cloth or paper towel and then place a lid over the pan.
Once the dough has cooled down, heat a small pan with remaining oil.
Add the mustard seeds, red chili powder and asafetida and fry until aromatic.
Add this seasoning to the dough and knead it well to incorporate.
Apply a little oil on your palm and start making tiny balls from the dough. My grandmother first makes a thin long rope and then pinches off tiny pieces from it and rolls them. Try to make them similar in size as they will cook evenly.
Place them on a greased steamer tray or a flat bowl. Do not overcrowd the tray. We could place upto couple of layers but not more than that.
Place the steamer on the gas and let the water come to a boil. I steamed mine in the Instant Pot. I turned the pot on Manual and let it heat up.
Once the water started boiling, I placed my tray inside. I turned off the pot and then switched it to the steam mode. I let it steam for about 12 minutes with the vent open.
Let the ammini Kozhukattai rest for at least 15 minutes before serving. They would appear very moist as soon as they come out of the steamer. But once they rest for about 10 minutes, they would harden up perfectly.