Chop or slice the mushroom and set aside
Add the onion and ginger/garlic paste to a blender and blend into a smooth paste. Add a few drops of water if required
Soak tomatoes in boiling water, remove skin and blend into a puree
Heat the oil and add the cinnamon stick, bay leaf, star aniseed and black elachie. Once it becomes fragrant add the onion mixture and curry leaf
Sauté the onion on low heat until it turns slightly brown
Add the tomato together with the chilli powder, turmeric, coriander and cumin. Mix it well. Cover and simmer until tomatoes are cooked or you see the oil surfacing to the top
Add the mushroom and yogurt together with 1/4 cup water. Season with salt
Cover and simmer until the mushrooms are cooked and the sauce thickens. Add a pinch of sugar if the tomatoes are too acidic. Add a teaspoon of butter and give it a mix