Butternut Squash Lasagna

Bahan-bahan (8 porsi)

• 1 large butternut squash (about 2 ½ pounds)
• 3 tablespoons olive oil (divided)
• 2 ¼ teaspoons kosher salt (divided)
• ½ teaspoon ground black pepper (divided)
• 1 large yellow onion (halved then cut into 1 ½-inch wedges)
• 1 head garlic
• 3 tablespoons unsalted butter
• ⅓ cup all-purpose flour
• 3 ½ cups low-fat milk
• 1 cup grated Parmesan cheese (divided)
• 1 cup shredded low-moisture part-skim mozzarella (divided)
• ⅛ teaspoon ground nutmeg (freshly grated if possible)
• 16 ounces low-fat cottage cheese or part-skim ricotta
• 2 large eggs
• 12 ounces frozen chopped spinach (thawed and squeezed very dry)
• 1 tablespoon finely chopped fresh sage (plus additional for serving)
• 12 to 15 sheets no-boil lasagna noodles (as needed to cover layers)
• Kosher salt and freshly ground black pepper