1
Preheat oven to 350 degrees F (175 degrees C).
2
In a skillet over medium-high heat, cook mushrooms, onions, and garlic in olive oil until onions are tender. Drain excess liquid and cool. Boil spinach for 5 minutes. Drain, then squeeze out excess liquid. Chop spinach.
3
Combine ricotta cheese, Romano cheese, spinach, salt, oregano, basil, pepper, and egg in a bowl. Add cooled mushroom mixture. Beat with an electric mixer on low speed for 1 minute. Lay 5 lasagna noodles in bottom of a 9x13 inch baking dish. Spread one third of the cheese/spinach mixture over noodles. Sprinkle 1 cup mozzarella cheese and 1/3 cup Parmesan cheese on top. Spread 1 cup spaghetti sauce over cheese. Repeat layering 2 times.
4
Cover dish with aluminum foil and bake in a preheated oven for 1 hour. Cool 15 minutes before serving.
