Cook the pineapple pieces in 1/4 cup of water with turmeric powder, chili powder, sugar, and salt until soft.
Grind the grated coconut, mustard seeds, green chilies, and cumin seeds into a smooth paste.
Add this coconut paste to the cooked pineapple. Stir well and cook on low heat for about 10 minutes until the excess water evaporates.
Turn off the flame and let it cool slightly, then stir in the curd. (Do not boil after adding the curd).
Finally, heat coconut oil in a pan, splutter mustard seeds, then add dry red chilies and curry leaves. Pour this tempering over the pachadi.