Combine cottage cheese, capsicum, green chillies, cumin powder, chaat masala and salt in a bowl and mix well.
Apply butter on bread slices. Place four slices on a worktop and put a spoonful of cottage cheese mixture on the bread slices, cover with remaining bread slices and apply some more butter on top.
Preheat a non-stick sandwich griller. Grill the sandwiches till grill marks appear on them.
Cut into triangles and serve immediately with tomato ketchup.