Think this classic of tender meat and rich gravy topped with mashed potatoes is the ultimate comfort food? The cook who has spent 5 hours preparing it might disagree. The traditional version of this dish of meat and gravy topped with mashed potatoes is time-consuming to make, and the end product is a bit heavy for modern palates. We streamlined the process by building and serving the pie in one skillet and by using lean ground beef rather than braised chunks of meat. To keep the meat tender…