Remove the core and prepare the pineapple into bite size pieces.
Place chopped pineapple, turmeric powder, red chilli powder, water and salt into a pan. Cover and cook on medium heat till the pineapple turns soft.
In the meantime, grind grated coconut, green chillies, mustard seeds, cumin seeds, along with a few tablespoons of water to a smooth paste. Set it aside.
Open the lid, add chopped ripe plantain and give it a mix. While that is simmer, mix 2 tbsp water with 4 tbsp of yogurt.
Add the ground mixture into the curry, mix well and allow it to cook for another 3-4 minutes. Dump in the grapes and sugar, stir and pour in the yogurt.Mix well and turn off the heat.
For the tempering: Heat a small pan, add mustard seeds and let it splutter.Add in dry red chillies, curry leaves and sliced shallots. Sauté for a minute and add this to the curry. Serve with hot rice and enjoy!