1. Heat oil in a pan and add in the fennel seeds, onions and curry leaves. Also add in the salt. Saute for 3-4 minutes till the onions are soft.
2. Take a small mixie jar and add in the garlic and ginger. Add in the cinnamon, clove, cardamom, kalpasi (stone flower) and star anise. Grind everything with half a cup of water to a very fine paste.
3. Add in the ground paste to the pan. Saute for 3-4 minutes.
4. Add in the chopped tomatoes.
5. Saute till the tomatoes are cooked and juiced down. It will take about 3-4 minutes on a medium flame. Add in the red chilli powder, turmeric powder and coriander powder. Saute for a couple of minutes. Add in the black pepper powder and the chopped mushroom. Mix well to combine.
6. Keep the flame on low and cover the pan with a lid and let it simmer for a couple of minutes. Let the mushroom absorb all the flavour from the masala. In the mean time, grind the coconut and cashews with a cup of water to a very smooth paste. Add it to the pan. Wash the mixie with half a cup of water and add back to the pan.
7. Cover the pan and let the flame be low. Let the curry simmer on a low flame for 15 minutes. Remember to stir once every couple of minutes so the masalas dont scorch at the bottom. The flavour develops and the curry becomes unctuous during this slow simmer.
8. The chettinad mushroom masala is ready when a film of fat / oil starts to appear on top.