Should lasagne be frozen cooked or uncooked?

You can do it both ways, but uncooked is better. Prepare the lasagne, cook all the ingredients that need cooking, then freeze them in foil containers instead of putting them into the oven. This way they'll be ready to be baked in the oven as soon as taken out of the freezer, no need to thaw. You can also freeze the lasagne after they've been baked in the oven, but you should only do this for leftovers, not intentionally. When you freeze them baked and then re-heat them in the oven, it means they're going to be baked twice and they won't be as nice. Also see here for more detailed answers: