In a grinder blend the sweet corn, chopped boiled potato, onion, green chillies, ginger, garlic, chaat masala, all ground spice, cumin powder, bread crumbs, all purpose flour, cashew nuts, pepper powder, and salt with a sufficient quantity of water and lemon juice. Transfer this mix to a bowl. Take a few breadcrumbs and some all purpose flour separately in a different plate. This is for dusting the kebabs. Use a little oil to grease your hands. Make flat shapes from the ground mixture. Dust with the breadcrumbs and the all purpose flour. Fry the kebabs in boiling oil. Transfer to a serving dish. For the garnish, prepare a salad with sliced onion, red chilli powder, and lemon juice. Place a lemon wedge and mint sprig on the kebabs for garnishing.