Mix all the spices ( except chaat masala) and corn flour in mashed potatoes. Now add all the vegetables in above mixture and mix well. Now divide the mixtire in 15 equal parts and make tikki like shape. Heat oil in a pan. Take tikki one by one and roll it over crumbled bread and fry it in oil till golden brown. Now keep it on absorbant paper and prinkle chaat masala over it. Serve hot with tomato ketchup or mint chutney.