If you bake two lasagnas and then stack one lasagna on top of the other, how many lasagnas do you have?

If you put them both in the same dish, you have one 'deep' lasagne.

If they are in separate 'covered' containers, and then stacked say in the fridge or freezer, you have two.

I gather you have never heard of the 100 layer lasagna? 

Do you regularly take your brain out and play with it? If so STOP!

You still have two lasagnas, because both will still in their own pan.  You cannot remove an entire lasagna from a pan without it spreading out all over the place, so you cannot stack two laeagnas unless they still ARE in their separate pans.