To roast red peppers in the oven, line a baking sheet with aluminum foil, and preheat the oven to a temperature of 400 degrees Fahrenheit. Cook the peppers on one side for approximately 20 minutes, then flip them over and repeat. Approximately six whole peppers fit a standard-sized baking sheet.
When placing the peppers on the lined baking sheet, turn the peppers so that their stems all point to the side in the same direction. To create a non-stick surface, consider coating the foil with a nonstick cooking spray beforehand. Cooking oil also works, but remember that olive oil smokes excessively at high temperatures. After the allotted time has passed, check to ensure the peppers are fully roasted. The finished product appears softened, charred and slightly collapsed.
Another method of roasting peppers in the oven is to use the broiler function. First make sure that the oven rack is no less than 8 or 9 inches from the broiling element, as otherwise the skin chars before the pepper is adequately softened. Turn the broiler on high, and insert the baking sheet. Remember that the broiler introduces direct heat, so it is essential to mind the peppers throughout, giving them a quarter turn every five minutes and cooking them for a total of 20 to 25 minutes. Do not be alarmed if the exterior of the skin is thoroughly charred, as this is removed before further preparation or serving.