As soon as smoke begins to release from the charcoal, cover the entire plate tightly with a large bowl. Allow the charcoal smoke to get infused for 1 to 2 minutes. The more you do, the more smoky the baingan bharta will become. I just keep for a minute. Alternatively, you can also do this dhungar method once the baingan bharta is cooked, just like the way we do for Dal Tadka.