If you’re looking to get ahead, you can store the beef, gravy and all, in the Dutch oven and transfer the potatoes to a greased baking dish. Cover and keep in the fridge for up to 3 days. To reheat, leave the beef covered and place over medium-low heat. Uncover the potatoes and transfer to a 375°F oven. Cook both for 35 to 45 minutes or until heated through and the potatoes are lightly golden brown and crisp around the edges.