Cut the leftover rotis into small pieces and grind them into flakes. Keep it aside.
Heat oil in a pan and add the mustard seeds and peanuts. Fry until they are brown.
Add the chopped green chilli and curry leaves. saute for a minute.
Add the chopped onion and mix well.
Add turmeric powder and salt and fry until onions are translucent.
Cover the pan with a lid and let it cook over a low flame for 2 minutes.
Aff the prepared roti flakes and some salt and mix well.
Turn off the flame and add the lemon juice and coriander leaves. Mix until everything is well combined.