In a wide bowl, take the oats + wheat Atta. Add salt and mix well.
Sprinkle water slowly and gently rub the flour. Make sure to moist the flour. Do not wet it.
Add the flour to a blender and blend it for just a second to get lump free texture. Take small amount of flour in your fist and it should form a whole lump and when pressed it should crumble immediately. This is the right consistency for making the puttu.
In a puttu steamer (both cylindrical and bowl type works well), first fill 1/3rd of the fresh grated coconut. Then add half of the wet flour.
Now again add wet flour and fill the other half from the remaining coconut. And then fill remaining flour.
At last fill the steamer with rest of the coconut.
Steam it for 15 minutes.
Once done serve hot with kadalacurry(Chickpea Curry) and banana.