America’s Test Kitchen recipe which states, “The freezer dehydrates food, so we added extra chicken broth to keep our Make-Ahead Shepherd’s Pie moist. The filling looked soupy when we froze it, but once reheated, it mimicked the original. Our potato topping soaked up too much of the beef mixture as we reheated the pie, so we strategically layered our other ingredients to create a makeshift barrier. To prevent the topping from turning grainy, we turned to waxy red potatoes. They packed fewer amylose molecules, the culprit behind a coarse mash.”