soak idli rice / sona masuri rice and fenugreek for at least for 5-6 hrs. also soak urad dal in a separate vessel for 2 hrs.
drain the water completely. you can use the same water for grinding.
first grind the soaked rice with required water. make to smooth paste.
take cooked rice in the blender and add little water and make it into a smooth batter.
transfer this to a large container.
now take urad dal in the same blender and add little water at a time and make it into a smooth batter.
make fluffy batter and transfer this to the same container.
give a good mix.
cover and ferment in a warm place for 12 hours.
you can see the batter has raised slightly indicating its well fermented.
take out the required portion of batter and refrigerate the rest of batter.
grease idli plates with little oil.
spoon the batter into each moulds.
place this idli plates into steamer and steam for 8 to 10 mins in a medium flame.
once it is steamed, remove it and let it cool for a bit.
your idli with cooked rice or cooked rice idli is ready. serve it with chutney or sambar.