Really, casseroles and stews don't need dressing up when you are reheating them as leftovers. Most slow cooked dishes like that will improve with a day or so sitting in the fridge, so simply reheating makes for a very gratifying supper. I can't resist some extra cooking though, so I did a Desperate Dan-esque pie with the last of the Beef and Guinness Casserole as the filling. Only pastry horns though.
Any similar dish can be given the same treatment. If you need a shortcrust pastry recipe, one can be found here. It's best if the filling goes in a room temperature- if it's hot the steam will make the pastry soggy.