Whisk the curd well, add chopped onion, chopped cucumber, chopped tomato, chopped green chilli, chopped coriander leaves, red chilli powder, chat masala powder, roasted masala powder and salt into it.
Mix it properly , raita is ready.
Take one slice of bread and spread 2 tbsp raita over it, cover this slice with another bread slice.
Repeat the same process to make more sandwiches.
Heat a tawa, put 1 tsp oil on it.
Once the oil is heated, add 1/3 tsp of mustard seeds and 5-6 curry leaves into the hot oil.
when the mustard seeds starts cracking, put the raita stuffed bread slices on it.
Roast the sandwich from both side till it turns light brown on low flame.
Take it out on a plate and cut it diagonally into two pieces .
Ready to serve with tomato ketchup or green chutney etc.