It’s very convenient to freeze leftover casseroles and lasagna for another meal on another day. The problem being if you freeze your dinner in a baking dish, that’s lost to you until you cook your meal. A better way is before freezing, line the baking pan with aluminum foil leaving some edges overlapping the sides of the dish. Freeze. Once completely frozen, lift the casserole out of the baking pan, wrap securely with more foil, and put back in the freeze. Now you’ve freed up that baking dish for other use.