This Shepherd’s Pie can be frozen before or after baking, but I do not recommend freezing in the dutch oven. If you plan on freezing this, then build the pie in an oven-safe and freezer-safe casserole dish, whether that is glass or aluminum or other. After building the casserole, skip the baking step since everything is already cooked. Cool it first in the fridge. Store it in an airtight container in the freezer and it will last for 3-4 months. To thaw, place in the refrigerator 24 hours in advance of cooking. Then place in a 400 degree oven for 30 minutes minutes covered then 10 minutes uncovered