To make the filling mix together mashed potato, cumin, ginger, green chilly, coriander, chilly powder and salt. Mix well and smear on 2 of the slices of bread. Cover the bread with the remaining slice.
In a bowl mix together besan, salt, ajwain, chilly powder, coriander powder, turmeric and water. Whisk to make a batter.
Heat a pan and drizzle oil. Dip the stuffed bread completely in the batter. Remove and shake off excess batter. Immediately place on hot pan. Cook for about 3 minutes and then turn the bread. Then using tongs lift the bread pakora and cook on all sides to make sure it is cooked from all sides. Remove and cut into a triangle.
For amchoor chutney, in a separate bowl add amchoor, sugar, black salt
Chilly powder, roasted cumin powder, salt and water. Whisk it to make sure there are no lumps. Pour it into a pan and bring it to a boil. Boil for 2-3 mins and remove from heat. Serve the chutney warm or cold.