Drain and rinse the peas and pressure cook them with salt and turmeric powder for 1 whistle on high heat and another whistle on simmer. Turn the heat off and allow to cool. In a pan, sauté the onion paste until fragrant. Then, add ginger-garlic paste and sauté until fragrant. Now add the tomato puree, cumin and coriander powders. Sauté for about 3 minutes. Then, add garam masala, chaat masala and chilli powder and sauté for a minute until everything is mixed together. Add the cooked peas and cook for a while, until the spices are absorbed into the peas. Adjust salt. Serve hot with patties.
To the potato mash, add brown rice flour, green chilli and salt. To make the pattice, make small balls of the potato mix and then apply slight pressure to flatten it evenly into thick discs.
Heat a tava (griddle) & cook the pattice gently on both sides on low or medium heat. Keep aside. Roast jeera, kadhi patta, chilli powder and garam masala. Powder to make ragda. Add the peas to this. To serve, take pattice and pour ragda on it.
Serve hot with tamarind chutney and sliced onions, and garnish with coriander.