Soak the Seppankizhangu in water for 10 minutes. Rub and wash well to remove all the dirt. In a big pot of water, add turmeric powder, salt and seppankizhangu.
Boil the washed seppankizhangu for 15–20 minutes until a knife slides in easily. Avoid overcooking, as it can become mushy. Drain, let it cool, peel the skin, and slice into ¼-inch thick rounds before roasting.
Let's marinate and roast
Add all ingredients under 'Marinade' into the cooked and sliced seppankizhangu. Mix well and keep it aside for 15 minutes.
Add coconut oil in an iron pan, add mustard seeds, chopped curry leaves.
Add the marinated seppankizhangu and toss well. Let it roast for 15 - 20 minutes.
It will crisp up beautifully on the outside and soft on the inside.