Add cardamom pods, bay leaves, black peppercorns, cloves and cinnamon.
Wait until the cloves swell up or the bay leaves begin to take on colour. This just takes a few seconds.
Now add chopped onions, stir and fry until they are golden brown.
Turn heat to low and add garlic, ginger, chillies, coriander powder, cumin powder, salt, garam masala, paprika, tomato puree and stir to mix.
Cool this mixture by placing pan into a bowl of cold water.
Now put in a tablespoon of yoghurt one spoon at a time incorporating it into the sauce each time before adding any more. Then add mushrooms and stir to mix. Turn heat to medium low, cover and simmer for about 10 - 15 minutes or until the sauce has reduced and turned fairly thick or until the mushrooms are cooked.