Wash and chop tomatoes and cilantro finely. Mix Besan and rice flour in a bowl. Add chopped vegetables, ajwain, salt, turmeric, and red chilli powder. Add water and mix well.
Heat pan. Pour a laddle of batter on the pan and spread it in a circle. Cook from both the side by flipping to other side.
Make small circles of tomato omelette and keep them aside.
Sandwich:
Make green chutney. Chop cucumber, potatoes, and onion into thin circles.
Toast the bread slices into the toaster.
Get three toasted bread slices on a plate. Apply butter and green chutney on each bread.
Place cucumber slices, potato slice and onion slice on one slice of bread. Sprinkle chaat masala on it. Add tomato omelette circle on second bread slice.
How to assemble:
Place the bread slice with vegetables at the bottom. Place bread slice with tomato omelette on it facing upword. Place third slice with butter and chutney on it facing downwords.