It was a vegan lasagne recipe, which I tried yesterday, since dd and SiL are no longer eating meat or dairy, except for FR eggs, largely from their rescue chooks. (Gdcs are still having cheese as well as eggs.).
The bulk ingredient of the tomato sauce was mushrooms - a lot - sliced and sautéed in just a little soy sauce, until most of the water from the mushrooms was shed, and then letting most of that evaporate.
I didn’t follow the recipe exactly, since I added finely chopped onion and celery, and spinach between the layers, but it was very tasty, which I dare was at least partly down to the soy sauce.
Shall be making a bigger one to take to dd’s on Sunday.