Put the pumpkin in a large pan of boiling salted water, add the turmeric, and cook, stirring frequently, for about 10-15 minutes, or until soft but not overcooked and mushy.
Heat the oil in a large frying pan over medium heat, add the mustard seeds, urad dal, and dried red chillies, and stir-fry for about 1 minute, or until the mustard seeds start to splutter.
Add the boiled pumpkin and jaggery or sugar. When the jaggery begins to dissolve, add the grated coconut and rice flour.
Cook for about 5 minutes, turning the vegetables over a few times until the pumpkin is tender. Remove from the heat and serve.