First grate potato and ONION.

LIKE this

Now add 3 TBS CORNFLOUR and mix it well.

Heat BUTTER in a pan

Now add SALT into potato mixture and mix it.

When BUTTER melts switch off the flame and spread potato mixture on pan

Give proper shape

Add BUTTER on corners. Now cover the lid and cook on medium flame for about r minute

After 4 min flip it and again add BUTTER and cook another side for about 3 minute

After 3 min flip it and cook both side till crisp.flip it couple of times

Potato Roasti is ready.now switch off the flame and serve with TOMATO sauce.