Add onion, coconut,green chilli, coriander, Curry leaves,salt, cumin seeds in a wide mixing bowl.
Mix it nicely by crushing onions with your hands for few minutes. This brings out more flavors from them.
Add ragi flour to it.Start adding warm water little by little and mix it nicely to form a dough.
The dough should be such that its easy to spread. It should not be too hard ,smooth-firm dough.
Spread a plastic sheet / aluminum foils / parchment paper /banana leaf on your kitchen slab.Grease it with a drop of oil.Take a orange sized dough and pat it evenly with your hands to a thin pancake.Wet your hands in between with water to ease the patting.Make 1-3 holes on the rotti so that they get cooked uniformly.
Heat the griddle.When its hot ,put the sheet on the griddle ( rotti side facing the griddle ). Cook the rotti along with the sheet for 30 sec and then slowly remove the foil.Rotti gets transferred from sheet to the griddle.
Cook on medium heat.Pour some oil in the holes and all over the rotti.Cover and cook till it becomes slightly brown in colour.
Then flip the rotti and continue cooking for about a minute or so till the rotti becomes crispy.
Repeat the same with the remaining dough. Serve the rottis hot.
Ragi rotti is ready to be served. Serve it coconut chutney / chutney powder + yoghurt / chutney powder + butter / Uchellu chutney /any chutney