Tindora masala (dondakaya masala) curry

Ingredients

• 1/2 KG tindora (dondakaya)
• 2 big onions
• 1 teaspoon chilly powder
• 1 teaspoon mustard seeds
• 1 teaspoon cumin seeds
• 1 teaspoon urad daal
• 5 tablespoons tamarind pulp
• 1 tablespoons jaggery powder
• salt to taste
• oil