Soak the batana overnight. Pressure cook with little salt, sufficient water, turmeric, baking soda and large chunks of potatoes for 5 to 6 whistles.

Cool and remove pressure. Heat oil add the spice powders leaving the chat masala and amchoor powder. Add tomatoes, salt. Cover and cook till oil leaves.

Now add the white batana with the water. Add remaining spice powders. Add chopped coriander. Add water to make a liquid consistency.

Cover and simmer for 7 to 8 minutes.