Heat one and half tablespoons ghee in a non stick kadai and add cumin seeds. When it changes colour add ginger and garlic and sauté. Add carom seeds and sauté for another minute.
Add green chillies and garam masala powder and mix. Add colocassia and sauté for two to three minutes. Add salt, dried mango powder and crushed peppercorns and sauté till the mixture leaves the side of the kadai.
Remove from heat and set aside to cool. Divide the mixture into sixteen equal parts and shape them into tikkis. Heat a little ghee in a non stick pan, place few tikkis at a time on it and shallow-fry till golden on both sides.
Drain on absorbent paper. Serve hot sprinkled with chaat masala.