Rinse the leaves and then chop then finely.(You can remove the thicker veins towards the base of the leaves if you want)
Heat the mustard oil till it starts smoking.
Add cumin seeds, let it splutter.
Add broken red chilli and chopped green chilli and fry for half a minute.
Add the chopped radish leaves.
Add salt and turmeric, mix well.
Let it cook for 3 to 4 minutes.
Add chilli powder if you want and stir.
Cook uncovered on a midium flame stirring in between.
Keep stirring till the liquids gets evaporate.
When it gets cooked and it looks dry, remove from fire.(you can make it more crispy if you want by frying it for some more time)
Serve mooli ka saag hot as a side dish along with rice and dal or you can also serve with phulkas or chapatis.
Notes
It is advisable to cook uncovered, to retain green color of the leaves.The quantity of leaves becomes less after it gets cooked hence you can increase or decrease the quantity of leaves as per your requirement. Its better if you cook, just before having lunch or dinner as it tastes great when it is hot and crisp.