Take gram flour, remaining turmeric powder, chilli powder and salt in a bowl, add sufficient water and whisk well to make a batter of coating consistency.

Spread a generous portion of potato mixture on 4 bread slices and cover with remaining bread slices.

Heat sufficient oil in a kadhai.
Cut sandwiches into triangles, dip in the batter and deep-fry in hot oil till golden brown. Drain on absorbent paper.

Serve hot with tomato ketchup.