In a glass plate or directly on the microwave tray, keep washed potatoes along with a small bowl of water so that the potatoes don't get dried and wrinkled. Microwave on high for about 4-5 minutes till potatoes are done. Keep aside for cooling.
In the meanwhile, take a big glass bowl, add the oil and jeera to it and microwave for 2 mins.
Add the onions to it and microwave for another 4 minutes till the onions soften and start to turn pink.
Now add the tomatoes and microwave for another 4 mins till tomatoes look somewhat cooked.
In the meanwhile, peel and dice the potatoes.
After the tomatoes are done, add the peas and all masalas and microwave for another 2-3 minutes.
Add the potatoes and microwave for another minute or so and let it rest for about 5 minutes so that the flavors mix well.
Serve with hot rotis :D.