To make the filling, mix all the ingredients together in a bowl. Fill the okra with equal quantities of the mixture and set aside.
To make the sauce, mix the chilli powder and turmeric in a small bowl with 2 tablespoons water.
Heat the oil or ghee in a deep, heavy-based pan over low heat, add the onion and fry for 3-4 minutes, or until translucent and glossy. Add the chilli powder mixture and stir-fry for about 3-4 minutes, or until all the moisture has evaporated.
Then add the stuffed okra, increase the heat to medium, cover, and cook, stirring occasionally, for 7-8 minutes.
Remove from the heat, stir in the yoghurt, and season with salt. Return to the heat and cook, stirring occasionally, but carefully, for about 5 minutes, or until the sauce is quite thick. Remove from the heat and adjust the seasoning, if necessary.