In a bowl mix together rava,curd,water and little salt.
Mix well and make it into smooth thick batter.
Grease a tray with oil. Before pouring the batter into tray,mix baking soda and 1 tsp oil and beat the batter for a minute.
Immediately pour the batter into the greased tray.
You can either use pressure cooker without weight or idli / rice vessel for cooking dhokla.
Pour 1 glass of water in vessel and place the tray inside the vessel with a stand below the tray.
Cover and cook on high flame for 5 mins initially and on medium flame for another 10 mins.
After 15 mins ,remove from vessel and let it cool for 5 mins.
For seasoning, heat oil, add mustard seeds,let it splutter, add remaining ingredients mentioned under for seasoning.
Pour this on the dhokla ,cut it into square size pieces.
Serve hot with mint chutney.