Slice the mangoes. Cook the mango slices, slit green chillies, few curry leaves, chilly powder, turmeric powder and salt adding enough water and cook covered until the mangoes are done. It will take around 15 mts at medium heat.
Grind the coconut and cumin seeds to a very fine paste. After the mangoes are done, add the ground coconut paste. Cook for a few minutes at low heat.
Add the beaten yoghurt, again at low heat. Mix well and cook for a few more minutes at low heat stirring in between, until it is heated through.
In another pan add oil and splutter the mustard seeds. Add dry red chillies and curry leaves. Pour this over the curry and sprinkle 1/4 tsp fenugreek powder. Mix well and check for salt.
It is having a grest combination with boiled rice.
To make pineapple pulliseri, replace mango with pineapple and follow the same procedure.