In a bowl mix potato, cilantro, ginger, green chili, salt, cumin seeds, and mango powder well.
Lightly butter the bread slices from one side and other side spread layer of thin potato mixture evenly, and brush the butter over the mixture.
Heat the skillet over medium heat and put the bread slices over the skillet putting the potato mixture side down.
Let it cook for about 2-3 minutes or till it is golden brown from bottom. Note: if you turn too quickly the spread will start coming out. Turn it over; put one slice of cheese and tomato slices covering the bread slice.
Now put the other slice of bread potato side down over tomatoes and grilled both sides until sandwich is golden brown and cheese has melted.
Potato Sandwich is ready, slice them diagonally. Serve the sandwich with Hari Cilantro Chutney and side of Carrot Pickle.
Slice them in small squares and serve them as snack. You may use leftover dry vegetables like Aloo Gobi (potatoes with cauliflower) or Aloo jeera, mash the leftover vegetables and follow the same steps. You can also use a multigrain or whole wheat bread of your choice.