Rinse & Dry: Rinse eggplants under cold running water. If there is a sticker on them, remove it. Dry with a kitchen towel or a paper towel. Set them aside. There is no need to peel the eggplant for fire roasting it.
Prepare your gas range: Line the base of a gas range with aluminum foil making sure to keep the burners exposed. I usually cut out the part where the burners are located to make it easier for cleaning purposes after the roasting process is completed.
Turn the burners on: Turn the burners on medium-heat and place eggplants directly on an open flame. I usually put 2 eggplants on the larger burners and 1 on the smaller ones.
Roast: Roast eggplants for about 15-20 minutes (depending on their size), turning every 5 minutes or so using a pair of tongs being very careful to not to burn yourself. You will know that it is fully roasted when the skin is burnt and flaky and the flesh is soft.
Let them cool: Transfer the now-fire roasted eggplant onto a plate and let them cool. This may take between 10-15 minutes.
Peel & Drain: Place a colander over a large bowl. When eggplants are cool enough to handle, peel them under cold running water by gently removing the black skin making sure to keep the flesh intact. If some burnt bits of skin are left behind that is okay. Discard the rest of the skin. Transfer the eggplant flesh to the colander and let it drain for 10-15 minutes*. Alternatively, you can skip the whole peeling under running water part and use a small spoon to separate the white flesh from the charred skin.
Use it in your recipe or freeze for later use: When ready to use, give it a rough chop or mash them on a cutting board (or food processor) according to the recipe you are following. Or, freeze for later use.