To roast vegetables, cut the vegetables of your choosing into a form like slices or cubes and toss in oil and any seasonings desired. Spread evenly onto pan and roast for 35-40 minutes at 430 degrees Fahrenheit, stirring occasionally.
While most vegetables cook for similar amounts of time on the same temperature, it is good to look into vegetable cook times for the ones you chose, and to pay mind to how large or small of an amount you're cooking as it could determine cook time. For example, peppers, cauliflower, eggplant, zucchini, asparagus and baby leeks all cook for a short 15 minutes, while the majority of others is best at the aforementioned 35-40 minutes. Also, a large quantity of vegetables may need to be cooked up to 20 minutes longer, while a small quantity may need up to 10 minutes less.
Any oil or butter may be used, and while a roasting pan is preferred, a baking pan also works - though it should be lined with foil to steer clear of burns and messes. Avoid cooking at too low a temperature, as anything below 400 degrees Fahrenheit could overcook the vegetables without caramelizing them as is desired. Test the process along the way to assure good quality, a thoroughly roasted vegetable is soft on the inside and has a caramelized exterior with a subtle crunch.