To roast your own peppers, preheat the broiler to high and position a rack 6 inches below the heat source. This is usually the second level. Place the whole peppers on a baking sheet and broil until blistered on all sides, turning every couple of minutes. Set aside in a bowl and cover for at least 15 minutes, or until cool enough to handle. Remove the skin and seeds. You can make this ahead of time and refrigerate in an airtight container for up to 4 days.