This super-simple casserole is a great way to use leftovers. Try the recipe with turkey and turkey gravy, or beef and beef gravy.
To thaw frozen mixed vegetables, place them in a colander or strainer and rinse with warm water until they are thawed. Drain vegetables well before adding them to the gravy mixture.
Use small cookie cutters to create holes in the top pastry crust. Save the cutouts and arrange them on the top crust, leaving the holes open, before baking.