Peel the potatoes and cut them into small chunks. Set aside.
In a wet grinder- add everthing under "For the wet chutney paste" and make a fine paste. Add water if needed. Set aside.
Heat oil in a heavy pottom pot until a bit smoky.
Add the cumin seeds, hing, green chillies and ginger all at once and saute for a minute or so. Dont let burn.
Add the potato chunks next, add a bit of salt and saute the potatoes in oil for a few minutes to brown their edges.
Once the potatoes are slightly browned, immediately add the onions. Saute for a few minutes till the onions are transculent but dont brown them.
Add all the powdwered spices - corinader, turmeric, roasted cumin powder and chaat masala next. Add 2-3 tbsp of water and saute the spices with oil for a few minutes till you see little bubbles of oil seperating.
Add the boiled peas next along with all the liquid. Check and adjust the salt. Coved the lid and let the peas cook with everrthing for about 20 minutes on low medium heat till the poatoes are tender.
Once the poatoes have cooked, add the wet chutney paste, mix nicely, you can mash the peas a bit for a thicker consistency. Cover and let everything simmer for another 10 minutes.
Serve warm with kulchas. You can add chopped onions, tomatoes, green chiilies and fresh lemon juice on top.