Fry bitter-nut vetral in a little oil and keep aside.
Pour a little water on the rice flour so that it just dissolves, mix well and keep aside.
Heat the pan with the oil and add mustard seed, urad dal and fenugreek seeds fry until it becomes brown.
Add curry leaves and add garlic and chopped onion fry until the garlic becomes soft and add the chili powder and fry.
Now add the tamarind juice and allow it to boil. Then add the bitter nut vetral and salt to the boiling solution.
Add rice flour and water solution to this.
Lower the heat and let it boil for 10 min.
Remove from the stove when the solution thickens.