Soak the tamarind ball in 1 cup of hot water. Let it soak for 15-20 minutes.
Rub the tamarind with your fingers to remove the pulp. Strain the liquid, using a sieve. Press down the pulp using a spoon.
Alternately add 1 tbsp tamarind paste in one cup of water.
Wash and wipe the mushrooms with a kitchen towel.
Cut them into slices or chunks.
Heat oil in a pan over medium heat.
Stir fry the sliced onion till it becomes light brown in colour.
Add the ginger, green chilli and garlic pastes. Stir fry for one minute.
Add kokum if you are using any.
Add the mushrooms and stir fry till they become a bit soft.
Add 2 tbsp of xacuti masala or spice mixture. Mix well.
Add the tamarind water, vegetable stock, salt and sugar. Mix well.
Cover the pan and allow the curry to simmer over low heat for 5-10 minutes.
Add coconut milk and chopped fresh coriander. Mix well.
Serve Mushroom Xacuti with some plain rice or poee.