1. Heat the oil in a large nonstick skillet over medium-high heat. Add the onions, zucchini and mushrooms; heat 5 minutes or until tender, stirring. Remove from heat; set aside. In a small bowl, mix the ricotta, Parmesan and pepper.
2. To assemble, place 3 lasagna noodles in the bottom of a 2-quart rectangular baking dish. Spoon half the ricotta mixture over the noodles. Top with half the veggie mixture, half the pasta sauce and half the mozzarella. Layer with remaining noodles, ricotta mixture, veggie mixture and sauce.
3. Bake, uncovered, in a 375 degree oven for 30 minutes. Sprinkle with tomato and remaining mozzarella. Bake 5 minutes more or until heated through. Let stand for 10 minutes before serving. Cut into 6 pieces.