Boil the cololasia in a pressure cooker for 3 to 4 whistles. Cool it and peel them. Cut into half lenthwise.
Heat the oil in a frying pan, add mustard seeds. When it pops up, add urad dhal and curry leaves and fry till the dhal turns light brown. Then add the cooked cololasia, salt, sambar powder, turmeric powder and mix well. Turn gently now and then and roast till it become light brown. Add curry leaves and mix well.
Note: You can also add one onion chopped finely while frying.