- heat oil in a frying pan and add mustard seeds, urad dal and fennel seeds to the oil. Then add onions and curry leaves. after onions getting slightly brown colored add mushrooms which are already cut into pieces of inch length. add salt and sprinkle some water and make mushrooms cook well.after mushrooms get cooked and see that no water is left in the curry. at this stage add pepper powder and switch off the stove. Serve hot.