Hey dear same happens to me ..then I leave making dahi bara. Then my friend gives me recipe ..she told me first soak the urad nd mong dal for 2 3 hours nd then grind it ..add salt ,1 pinch soda nd mix it well In same direction for 10 min ..nd then make bara. Then put it in hot water nd dip for 10 min then pour it properly nd then add in dahi . Touch wood its became soo soft as market . U can try it