One of the nice things about roasting roots is that you can do them in advance. Just roast them slightly less than completely done—I look for a fully tender root but with little to no caramelization on the skin. Let them cool completely, then store until you are ready to make dinner. Then spread them out on the baking sheet as you would if you were roasting them for the first time and reheat at 375°F (190°C). Know that you can reheat (or roast for that matter) at different temperatures if you already have the oven on for something else, making your oven do double duty. Just remember, the hotter the oven the faster the food will cook (read: burn), so don’t abandon it.