Marinate the fish pieces with pepper powder, turmeric powder, salt & lemon juice. Keep it for half an hour. Shallow fry the marinated fish for just 2-3 minutes.
Heat oil in a pan. Splutter cardamom,cinnamon & cloves. Add crushed ginger garlic & green chillies. Add small & big onions. Once the onion becomes soft add thin coconut milk. Let it boil. Add the fried fish pieces & add salt.
When the gravy becomes little thick add medium coconut milk.After that add tomatoes & curry leaves when the gravy becomes thick. Once the tomatoes is cooked add thick coconut milk & just heat it.
If you require a thicker gravy please add 2 teaspoons of cornflour to this.