Steps
1. In a mixing bowl, combine the mashed potato, grated cheese, ketchup, mayonnaise, salt, pepper, red chili powder, cumin powder, and garam masala.
2. Spread butter on one side of each bread slice.
3. Spread the potato and cheese mixture evenly on the non-buttered side of one bread slice.
4. Place the other bread slice, buttered side up, on top of the mixture.
5. Heat a non-stick pan over medium heat and place the sandwich in the pan.
6. Cook until the bread turns golden brown and crispy, then flip and cook the other side as well.
7. Remove from heat and cut the sandwich into halves or quarters.
8. Garnish with fresh coriander leaves and serve hot.