1.clear kidneys .cut into 4 cm (about 1 1/2) pieces.
2.grind onions coriander leaves, green chillies, garlic, ginger and fennel and mix with curds.
3.roast cinnamon, cardamom, cloves, cumin and mix with curds and ground masala.
4.add salt and black salt .
5.marinade kidneys for 1 hour in above mixture.
6.put kidneys on a skewer.cook on charcoal and baste with oil . keep turning regularly to ensure even browsing. cook for 10 minutes.
7.remove from fire. baste again with oil and cook for another 15 minutes. serve hot with onion salad.