Prepare peppers. Start by preparing your peppers by cutting them in half lengthwise and then removing the stem, seeds, and ribs (the white portion inside the pepper). Pour the olive oil over the peppers and rub it over the outside and inside.
Bake peppers. Place the peppers on a baking sheet so that the skin faces up. Put the baking sheet on the top rack under the broiler and let the peppers broil for approximately 5 minutes or until the skin begins to blister and blacken. If needed you can shift the peppers around to help blacken as much of the skin as you can.
Sweat the peppers. When the skin of your peppers has blackened carefully remove them from the oven and place them in a bowl or airtight container together. Cover the bowl or container with a lid or a piece of aluminum foil or plastic wrap. Let the peppers sit for 30 minutes.
Remove the skin. Once your peppers have been sweating for at least 30 minutes and are cool enough to handle you can remove the skin. Use your fingers to gently peel off as much of the skin as you can. DO NOT run the pepper under water as you do this because it can wash away some of that nice charred flavor it got from roasting.