Onion tomato tikki sandwich is a delicious and filling sandwich made with a flavorful onion and tomato tikki patty. The tikki is made with a mixture of mashed potatoes, onions, tomatoes, and spices, which is then shaped into patties and shallow fried until crispy. The tikki is then sandwiched between two slices of bread along with some chutney and veggies, making it a perfect snack or breakfast option.