Preheat the oven to 450°F to 500°F
Wash and dry the sweet peppers
Leave peppers whole or cut them in half and remove seeds
Place peppers on a baking sheet lined with foil or parchment
Brush lightly with oil if desired
Roast for 20 to 30 minutes, turning occasionally, until skins are blistered and charred
Remove peppers from the oven
Place them in a covered bowl or sealed bag for 10 to 15 minutes
Peel off the skins if desired
Remove stems and seeds if not already done
Use immediately or store in the refrigerator