Butternut Squash, Caramelized Onion, and Spinach Lasagna

This vegetarian pasta dish is sure to appeal to any gourmet at your dining table.
Preheat the oven to 425 degrees.Combine the pumpkin, 1 tablespoon oil, sage, garlic, 1/2 teaspoon salt, and black pepper in a large bowl; stir to coat. Place the pumpkin mixture on a baking sheet greased with cooking spray. Bake at 425 ° C for 30 minutes or until the pumpkin is tender. Cool slightly; peel the garlic. Put the pumpkin and garlic in a bowl; mash partially with a fork.Heat the remaining 1 tablespoon of oil in a large roasting pan over medium-high heat. Add the onion and simmer for 4 minutes. Reduce the heat to medium-low; continue cooking for 20 minutes or until golden brown, stirring frequently. Put the onion in a bowl.Add 2 tablespoons of water and spinach to the roasting pan; turn up the heat to high. Cover and cook for 2 minutes or until the spinach wilts. Drain in a colander; allow to cool. Squeeze any excess liquid out of the spinach. Add the spinach to the onions.Heat 4 1/2 cups milk, bay leaf, and thyme in a medium saucepan over medium-high heat. Bring to a boil; remove from heat. Let stand for 10 minutes. Skip the bay leaves and thyme. Return the skillet to medium-high heat. Combine the remaining 1/2 cup milk and flour in a small bowl. Add to the pan, stirring with a whisk until smooth. Bring to a boil; reduce heat and simmer for 5 minutes or until thickened, stirring constantly. Remove from heat; add remaining 1/2 teaspoon salt, 1/4 cup cheese, red pepper and nutmeg.Place 1/2 cup of the milk mixture on the bottom of a 13-inch x 9-inch glass or ceramic baking dish coated with cooking spray. Place 3 noodles on top of the milk mixture; top with half the pumpkin mixture, half the spinach mixture, and 3/4 cup of the milk mixture. Repeat the layers, ending with noodles. Spread the remaining milk mixture over the noodles. Bake at 425 ° C for 30 minutes and remove from the oven. Sprinkle with the remaining 1/4 cup cheese.Preheat the grill.Bake for 2 minutes or until the cheese is melted and lightly browned. Let stand for 10 minutes before serving.