Soak the channa overnight or 10 hours and boil. Drain the water.
In a wide bowl add the cooked channa, potato, red chilli powder, amchoor powder, chaat masala and salt. Add finely chopped coriander leaves.
With a masher, mash the potato and slightly mash the channa and mix well. Our stuffing for the sandwich is ready.
Take a bread and spread butter on one side of the bread. On the other side add little green chutney(keep the chutney thick) and sweet chutney. Spread them well.
Add some grated cheese on this and spread some channa aloo mixture on it. Spread some more cheese on the top. Spread butter on another bread and cover this stuffed bread with the buttered side facing upwards.
Cook this in a sandwich maker. Serve hot.