Soak the sangar in haldi water for whole night. Put it in a pressure cooker and wait for 1 whistle. Turn off the gas. Strain the sangar through a strainer. Keep the strained water aside. Heat mustard oil in a kadahi. Now give tadka by adding mustard (grounded), hing, jeera and sabut red chilly. When the tadka is ready add the masala paste. Add curd, sangar and soaked amchur. ( soak it for a ½ hour). Add to the kadahi. If required add the strained water. Cook it for 10-15 minutes. You can enjoy this vegetable for 8-10 days if kept in a refrigerator. Serve hot with Dal Ke Parathe.