Cooking Method :
Wash and slice Brinjal in vertical rectangle shaped pieces. Rub in the salt and turmeric powder and set aside for sometime.
Grind ginger and garlic together into a coarse paste. Powder the spices Cumin (jeera), fenugreek, chilly powder and mustard.
Heat oil in a pan and fry Brinjal pieces. Shallow fry until they are tender and semi cooked. Drain and set aside on paper towels, so the extra oil is absorbed. In the same oil add sliced onions and fry till golden brown. You can add more oil if needed. Drain and take the onions out of the oil and keep aside. Add Ginger garlic paste to the oil and sauté on a low flame till a fragrance spills out. Take care not to burn it. Add the powdered spices, sauté for 15 seconds until fragrant. Add tomato sauce and sauté till the oil separates. Now add 2 cups of water along with fried Brinjal and onions. Bring to boil. Let it simmer for 3-4 minutes or until the gravy reaches the required consistency. Add salt and vinegar to taste. Garnish with coriander leaves or mint leaves as per your preference.