Wipe the mushrooms with paper or damp kitchen towel and using a knife slice them. Don't slice too thin. If using frozen peas, thaw them. Set aside.
In a pan/wok/kadhai, on high, heat up the oil to smoky point. Reduce the heat to medium & add the chopped onions & garlic.
When the onions start to soften & lightly brown, add the chopped tomatoes, green chilies, ginger, turmeric, coriander,amchoor and red chili powder and turn heat to medium-low.Let the tomatoes cook down and soften, cook this masala till you see oil separating on sides.
At this point turn heat to medium high & add the sliced mushrooms. Also add pinch of salt. Cook the mushrooms till they are tender. They will slowly release their water and start to shrink in size. I used white button mushrooms & it took they approximately 8 minutes to cook. The time will depend on the variety of mushrooms you are using.
Once the mushrooms are sweaty and have shrunk in size, add the peas,adjust the salt, snd also add the kasuri methi . Cover for 5 minutes on medium - low heat and let cook.
Finish with garam masala and garnish with chopped cilantro. You can also squirt little lemon juice/vinegar if you like. Serve immediately.