Preheat oven and boil a pot of water.

1. Turn the oven to 425 degrees F. Place the chopped butternut squash on a baking sheet and drizzle with olive oil and a sprinkle of salt. Roast until the edges are brown, about 25 minutes.
2. Put a large pot of water on a hot burner to boil.

Prepare the sauce. We’re making a roux and it’s not as hard as the fancy name sounds.

1. Melt the butter in a large pan that can go in the oven. Add the mushrooms and stir. Add the onions and stir again. Cook on low heat until both are soft, about 10 minutes, stirring often. Add garlic and cook for about 1 minute.
2. Sprinkle the flour into the mixture and stir. Cook for about 1 minute.
3. Slowly add the milk, stirring and scraping the bottom.
4. Sprinkle the mozzarella and feta cheese in (but hold about 1/4 cup of mozzarella cheese to sprinkle on top) and stir.
5. Add the spices–oregano, sage, nutmeg, salt and pepper and stir. Set aside.

Boil the noodles. 

1. Cook the noodles for only 5 minutes.
2. Remove the pasta from the water BUT KEEP 2 cups of cooking water.

Combine everything. 

1. Add the pasta to the large pan with the mushrooms and cheese sauce.
2. Stir in the spinach.
3. Add the roasted butternut squash.
4. Pour 1-2 cups of pasta water into the pot, stirring again.
5. Sprinkle with remaining 1/4 cup of cheese.
6. Bake, covered, for 20-30 minutes. Remove lid (or foil) and broil for 1-2 minutes before serving.