Preheat the oven to 355 degrees F; prepare a 9”x13” casserole dish by lightly greasing with some oil.
Spread a layer of tomato sauce on the bottom of the casserole dish, and add a layer of pasta.
Add a layer of eggplant, a third of the béchamel sauce, and a third of the tomato sauce.
Place another layer of pasta, followed by a layer of zucchini, one third of the tomato sauce, and half of the lemon ricotta.
Continue layering in the same manner and add half of the béchamel sauce on top. Add another layer of lasagna, then add mushroom and remaining béchamel sauce.
Cover with another layer of lasagna sheet, top with remaining tomato sauce, sprinkle Parmesan cheese on top, and transfer the casserole dish to the preheated oven.
Bake for 35 minutes until the cheese is bubbly and brown.
Once done, remove from oven, let it sit and cool for at least five minutes, then serve.