Cut mushroom into bite size pieces.
Heat oil in a pan & add cardamom, cinnamon & onion. Stir it till the onion turns golden brown colour. Add ginger garlic paste and stir for a few minutes. Add tomato paste along with spice powders and cook till the oil starts appearing.
Mix the cashew nut paste with one cup water and add to the curry. When it starts boiling add sliced mushroom & peas. Cook till the vegetables are done.
For cashew nut paste, soak 10-15 cashew nuts in warm water for 10 minutes and grind it with a little water. The gravy tends to be thick after sometime, so adjust the quantity of gravy accordingly.