Turn on your broiler. Line a baking sheet with tin foil. Place the 4 peppers on the foil, then put it in the oven on the highest rack, as close to the heat as possible. Broil until the skin is mostly black. It should take 5 or 10 minutes, keep an eye on it. Then remove the pan from the oven, flip the peppers, and repeat on the other side. (Here
is a great tutorial if you're nervous.) Place the peppers in a ziplock or in a covered bowl for 20 minutes to steam. Then carefully peel off the skins. Slit the peppers and discard the seeds and stems. Slice into 1-inch strips and set aside.