Wash the eggplant thoroughly. Pat it dry with a kitchen towel. Rub 1 teaspoon of cooking oil all over the eggplant skin. You can make small slits in the eggplant and insert the garlic cloves if desired. Place the eggplant directly over a medium-low open flame. Turn the eggplant every 2 to 3 minutes to cook it evenly. Alternatively, you can grill or roast it in an oven at 200°C (400°F) for 30-45 minutes, but it will not have a smoky flavor. 2. Continue roasting until the eggplant skin is charred and the flesh inside is very soft. To check if it's done, insert a knife or fork easily into the center of the eggplant. If it slides in without resistance, it is cooked. Remove the cooked eggplant from the flame and immediately place it in a bowl of cold water. Let it cool completely. 3. (Optional Smoky Flavor Step): If you want a deeper smoky flavor, use this technique. Take a small piece of natural charcoal. Heat it over an open flame until it glows red and smokes. Make small cuts on the roasted eggplant. Place the hot charcoal on a small heat-safe plate or aluminum foil. Place this next to the eggplant in a larger bowl or pot. Drip a few drops of oil onto the hot charcoal. It will start to smoke heavily. Quickly cover the bowl or pot tightly with a lid or another larger bowl. Let the smoke infuse for 1 to 2 minutes. The longer you leave it, the smokier the dish will be. Remove the charcoal before proceeding. 4. Once the eggplant is cool enough to handle, peel off its charred skin. Discard the skin. 5. Finely chop the peeled eggplant flesh or mash it with a fork. Set aside. 6. Heat 1.5 tablespoons of oil in a large pan or 'kadai' over medium heat. Add the finely chopped onions and garlic. 7. Cook the onions and garlic, stirring occasionally, for about 5-7 minutes until the onions become soft and translucent. Do not let them turn brown. 8. Add the chopped green chili and cook for 1 minute, stirring. 9. Add the chopped tomatoes to the pan. Stir well to combine. 10. Continue to cook the tomato mixture, stirring occasionally, for 8-10 minutes. Cook until the tomatoes are very soft and the oil begins to separate from the mixture at the edges of the pan. 11. Add the red chili powder to the pan. Stir to mix it thoroughly with the tomato mixture. Cook for 30 seconds. 12. Add the chopped or mashed eggplant to the pan. 13. Stir very well, ensuring the eggplant is fully combined with the onion-tomato spice mixture (masala). 14. Season with salt to taste. Stir and cook for another 4 to 5 minutes, allowing all the flavors to blend. 15. Stir in the chopped fresh coriander leaves. Your Baingan Bharta is now ready. Serve hot with flatbreads like phulkas, rotis, or chapatis. It also pairs well with rice or toasted bread.