Butternut Squash Lasagna

Ingredients

• 2 butternut squash
• 2 tablespoons olive oil
• 1/4 teaspoon salt
• 1/8 teaspoon pepper
• 5 cups milk
• 6 whole sage leaves
• 6 tablespoons unsalted butter
• 8 tablespoons all-purpose flour
• 3/4 cup grated Parmesan
• 16 dry lasagna noodles
• 2 cups whole milk ricotta
• 1 large egg
• 1/2 cup grated fontina
• 3 tablespoons chopped fresh parsley
• Finely grated zest of 1/2 lemon
• Pinch black pepper
• 5 ounces fresh baby spinach leaves
• 1 cup grated Parmesan
• 1 cup grated fontina

Directions

1. Peel the squashes with a vegetable peeler. Split each squash lengthwise, scrape out the seeds, and cut the halves crosswise into 1/4-inch thick slices.
2. Heat the oven to 450ºF. Cover 2 baking sheets with parchment, arrange the squash slices on them, and brush the slices with olive oil. Season with salt and pepper, then roast for 18 to 25 minutes, until the squash is tender.
3. For the béchamel, combine the milk and sage leaves in a microwave-safe measuring cup with a spout. Warm it in the microwave for 4 to 5 minutes, just until bubbles appear around the edges but the milk is not boiling. If you use a saucepan on the stove instead, take it off the heat as soon as it bubbles lightly. Let the sage sit in the milk for 20 minutes.
4. While the milk steeps, bring salted water to a boil in a large (6-quart) pot. Cook the lasagna noodles according to the package directions, about 8 minutes. Holding the pot over the sink, drain away the hot water, then fill the pot with cold water and keep the water running until the water in the pot feels cool. Leave the noodles covered with cold water so they stop cooking and lose some of their starch. Take the noodles out separately and lay them on a kitchen towel. If they cling together a little or a noodle tears, don’t fuss over it; all those layers are very forgiving.
5. Set a medium saucepan over medium heat and melt the butter for the béchamel. Whisk in the flour and cook, stirring the whole time, for about 1 minute, until the mixture is evenly bubbling. Keep it pale; you don’t want the flour to brown. Take the pan off the heat. With the sage leaves still in the milk, slowly whisk about 1 cup of the hot milk into the butter-flour mixture until smooth. Add the rest of the milk gradually, whisking until the sauce is smooth, then return the pan to medium heat. Bring the sauce to a gentle boil, whisking steadily. Lower the heat to a simmer and cook, still whisking, for 3 to 4 minutes longer, until the sauce thickens enough to cling to a wooden spoon. Remove the pan from the heat, take out the sage leaves, and discard them. Stir in the Parmesan, salt, and pepper. Taste, then add more salt and pepper if you want it.
6. For the filling, combine the egg and ricotta in a bowl, then mix in the lemon zest, parsley, fontina, Parmesan, salt, and pepper.
7. Turn the oven down to 375ºF. Spread about 1/4 cup of béchamel in a thin layer across the bottom of a 9x13 baking dish. Arrange 4 noodles the long way over the sauce, then cover them with 1/4 of the remaining béchamel. Add 1/3 of the spinach leaves, then 1/3 of the squash slices. Use heaping tablespoons to drop 1/3 of the filling over the squash. Build the same layers 2 more times, ending with 3 layers altogether: noodles, béchamel, spinach, squash, and filling. Add a 4th layer of noodles, spread the remaining béchamel over the top, and sprinkle with the Parmesan and fontina.
8. Bake the lasagna for 50 to 60 minutes, until it is golden brown and bubbling.
9. Let the lasagna rest and settle for 15 to 20 minutes before cutting it into serving pieces. Cover leftovers and refrigerate; they keep for at least 4 days.