Potato crusted cheesy cauliflower casserole.
I'd cook and then freeze.
definitely bake then freeze.
Well, I decided to freeze the casserole without the egg custard. I'll just add it fresh when I thaw it for dinner sometime soon. Thanks to those that answered!
I think you did the right thing. Custards, cooked or raw, tend to break once thawed. The water in the wet ingredients freezes and never reabsorbs. It leaves the custard curdled in appearance and a watery liquid in the bottom of the casserole.
Quiches freeze pretty well and are essentially egg custards with vegetables, or whatever other filling, mixed in.