My favourite sandwich in the world is a Mumbai sandwich. Indian Street Food makes me so happy and this sandwich is very popular in Mumbai or Bombay. I love it almost as much i love India. This sandwich like India is vibrant and a riot of colour and spices.
Add the potatoes, green peas, turmeric powder, green chilli paste, coriander and salt, mix well and cook on a medium flame for another minute.Squeeze in the lemon juice and mix.
Assemble
Butter 2 slices of bread. Spread a layer of butter on both sides of each slice. Generously spread the green chutney on one side of each slice.
Then layer one of the bread with potato, sprinkle with chaat masala if using and add the sliced tomatoes, cucumbers, beetroot (if using) and top with grated cheese. Top with the other slice of bread.
Toast in a pan (press down on it) until the sandwich is is golden brown. Cut and serve with tamarind and extra chutney if desired.
Notes
I haven't given measurements for most of the ingredients because the quantity of chutney is enough to make several sandwiches and you can adjust the ingredients in accordance with how many sandwiches you will be making.