Heat oil in a non-stick deep pan and saute cumin seeds, garlic and onions till tender and fragrant. Add mushrooms, and fry till brown all the moisture evaporates. Stir in salt and spices, and fry for a minute.
Add 3 and 3/4 cups of water, and once it comes to a boil, stir in rice and peas. Let simmer on low heat till water evaporates and rice is cooked through. Garnish with chopped coriander leaves and serve warm with a side of raita.