The most time consuming part of this recipe is washing and cutting the fresh mushrooms. However, I would not recommend using canned mushrooms in this recipe as they will be "lost" in the tomato sauce. A lot of time is saved by microwaving the mushrooms. I make the lasagne in a 20cm x 30cm pyrex.
This is one of the few pasta dishes that turn out well - delicious, even - on the shabbat hot plate. It should also turn out great without the shabbat hot plate by baking it longer (see notes). It is also very easy to prepare.