The brown sugar, cream, marshmallows and oatmeal streusel gives this casserole a taste similar to sweet potato pie, yet the dish goes great alongside meals as varied as low-key chicken dinners or festive holiday banquets. And the great part is, if you’re planning to use this for entertaining, you can make everything but the streusel a day ahead so you won’t be stressed at crunch time. Just cover the filled baking dish and pop it in the fridge. Take it out a few hours before you plan to bake it so the casserole can come close to room temperature, then you simply make your streusel and pop the whole thing in the oven.