Preheat oven to 425 F. Cut butternut squash in half, scoop out the seeds and place them open-side down on a parchment-lined baking sheet. Place the onion ( cut into large wedges) next to it and drizzle it with a bit of olive oil. Roast until fork-tender, about 30-40 minutes. Let cool. You could do this a day before or cook whole in an instant pot for 22 minutes. When the butternut is cool enough to handle, scoop out 3 -3 ½ cups of the flesh into a food processor. Add the roasted onion, olive oil, water, salt, pepper and garlic powder. Puree until very smooth. TIP: When using no-boil noodles, you want this to be extra loose & saucy, like a marinara sauce (so add more water if need be!). It should pour out of the food processor and you’ll need at least 4 cups of sauce. This can be made up to 4 days ahead.

In a large skillet, heat the oil or butter. Add mushrooms and shallots and salt, and saute over medium heat, until the mushrooms release their liquid and begin to brown. Add the garlic, sage and pepper. Cook until garlic is fragrant, about 2-3 more minutes, and turn the heat off. You could toss in some spinach at the end and wilt for extra nutrients. Taste and make sure the filling has enough salt and pepper. You could also add a little truffle oil to elevate. Make this up to 3 days ahead and refrigerate.

Using a fork, mix the ricotta cheese with the egg, nutmeg and salt. ( You really don’t need to add the egg, but it adds a lovely richness.)

In a greased 9 x 13-inch baking dish, add 1 cup of the butternut puree and spread out into a thin layer. Top with the first layer of lasagna noodles. Add half of the ricotta mixture and spread out evenly. Top with half of the cooked mushrooms/spinach. Sprinkle with ½ cup of the grated mozzarella and 2-3 tablespoons of pecorino cheese. Add the 2nd layer of lasagna noodles. Drizzle with 1 cup of butternut sauce; spread out the remaining ricotta mixture as evenly as possible. Add the remaining mushrooms and all the good bits (onions and sage) and sprinkle with ½ cup shredded mozzarella and 2-3 tablespoons pecorino cheese. Place the 3rd, final layer of noodles over the top. Lather with the remaining butternut Sauce and either sprinkle with the rest of the cheese or make the creamy béchamel sauce, spreading it over top. (See notes.).

Cover with parchment, then wrap tightly with foil and bake in 375 F oven for 40 minutes. You want a tight seal when using no-boil noodles. (You never want the foil to touch your food, especially something wet- the aluminum will leach into your food.) Uncover and continue baking 15-20 minutes until golden and bubbly. Let rest 10 minutes, cut into 9 servings.

Garnish with optional crispy sage leaves.