Brush eggplant with oil and roast it on a gas burner over medium heat. Frequently turn the eggplant upside down, until fully roasted. Once done, hold it under cold running water or in a bowl full of water. Cool it and peel off the blackened skin. Mash the flesh. Heat oil in a pan / kadhai . Add green chilli and onion and fry over medium heat until light golden brown. Add red chilli powder, turmeric powder, garam masala and salt and stir. Add tomatoes and cook until tender. Add green peas and mashed eggplant. Stir well. Fry for 5-7 minutes over medium heat.