I am making shepherd's pie soon for freezing, and have been given conflicting advice regarding freezing the mash potato topping. I've been told both to freeze only the mince base and make the mash fresh (but as these meals are neede for quick heating and cooking that might be counter -productive) or to freeze the whole thing, but that the mash will be drier once defrosted. Has anyone any tips on freezing mash potato, or reheating it, that would prevent this? would cooking straight from frozen rather than defrosting first, make any difference?
Once you've added the mash to the pie, let it cool completely then add grated cheese and a few cubes of butter. Cover tightly with tin foil and freeze. When you're ready to cook it, defrost it and cook as normal. The cheese and butter will melt into the potato, remoistening it.
You may also want to leave the mince a little wetter than usual so that the liquid can be absorbed into the mash from underneath during cooking.