Squash Filling

1. Place cubed squash in microwave safe vessel, add water, cover loosely, and cook until tender.
2. Remove from microwave and add salt and nutmeg.
3. Mash squash with a potato masher until mostly smooth.

Onion and Mushroom Filling

1. Quarter the onion pole to pole and slice quarters into 1/8 inch quarter moons.
2. Heat olive oil in large skillet over medium-high heat.
3. Add onions, mushrooms, and salt.
4. Reduce heat to medium-low.
5. Cook, stirring often, until tender and golden (about 15 minutes).
6. Off heat add pepper and thyme.
7. Place into a heat proof dish.

Ricotta Cheese Filling

1. In a bowl mix ricotta cheese and egg until smooth.

Tomato Sauce

1. In the same skillet used for the onions and mushrooms add the tomotoes, salt, and Italian herbs.
2. Simmer over medium heat until warmed through.
3. Preheat oven to 400 degrees.

Assemble

1. Coat a 9×11 baking dish with olive oil or cooking spray.
2. Spread ½ cup tomato sauce in the bottom of the baking dish.
3. Top with three lasagna noodles.
4. Spread half of the butternut squash filling over the noodles.
5. Evenly distribute half of the onion and mushroom filling over the squash.
6. Spread half of the ricotta filling over the squash, onions, and mushrooms.
7. Top with 1 cup tomato sauce.
8. Sprinkle over 2/3 cup shredded cheese.
9. Repeat for the second layer.
10. Top with the remaining noodles.
11. Spread remaining tomato sauce evenly over noodles to cover
12. Cover dish with foil.
13. Bake until hot and bubbling, about 45 minutes.
14. Remove foil, top with the remaining cheese and 3 tablespoons Parmesan and bake, uncovered, until the cheese is melted, around 10 minutes.
15. Cool for 15 to 20 minutes before slicing and serving.