Blend the tomatoes with fresh red chilies. Peel the potatoes and break with hands into small pieces. Mix coriander powder, cumin powder, turmeric and salt. Add the dry masala mixture to the potatoes and keep aside.
Heat oil in a pan and add panch-poran and dry red chilies. When the seeds splutter, add the tomato mixture and the potatoes. Add 4 cups of water and cook for 10-15 minutes on medium fire.
Garnish with chopped coriander leaves. Serve with hot puris.
Panch Poran Mix:
Mix equal quantities of cumin seeds, fennel seeds, mustard seeds, nigella seeds and fenugreek seeds.