Lasagna with Fall Vegetables, Gruyère, and Sage Béchamel

Ingredients

• B[SPECIAL_CHAR
• 2/3 cup all-purpose flour
• 6 cups fat-free milk
• 1/2 cup finely chopped onion
• 1/4 cup chopped fresh sage
• 2 tablespoons finely chopped shallots
• 1/2 teaspoon sea salt
• 1 bay leaf
• Filling:
• 1 tablespoon olive oil, divided
• 2 1/2 cups finely chopped onion
• 3 garlic cloves, minced
• 1 teaspoon sea salt, divided
• 1 (10-ounce) package fresh spinach
• 8 cups chopped portobello mushroom caps (about 1 1/2 pounds)
• 6 cups (1/2-inch) cubed peeled sweet potato (about 2 1/2 pounds)
• Cooking spray
• 1 cup (4 ounces) shredded Gruyère cheese
• 3/4 cup (3 ounces) grated fresh Parmesan cheese
• Noodles:
• 12 precooked lasagna noodles
• 2 cups warm water

Preparation

1. Preheat oven to 450°.
2. To prepare béchamel, lightly spoon flour into dry measuring cups; level with a knife. Place flour in a Dutch oven, and gradually add milk, stirring with a whisk. Add 1/2 cup onion, sage, shallots, 1/2 teaspoon salt, and bay leaf. Bring the mixture to a boil; cook 1 minute or until thick. Strain béchamel through a sieve over a bowl, and discard solids. Set the béchamel aside.
3. To prepare the filling, heat 1 1/2 teaspoons olive oil in a large nonstick skillet over medium-high heat. Add 2 1/2 cups onion and garlic; sauté 3 minutes. Add 1/2 teaspoon salt and spinach; sauté 2 minutes or until spinach wilts. Set aside.
4. Combine 1 1/2 teaspoons oil, 1/2 teaspoon salt, mushroom, and sweet potato on a jelly roll pan coated with cooking spray. Bake at 450° for 15 minutes.
5. Combine cheeses; set aside.
6. To prepare noodles, soak noodles in warm water in a 13 x 9-inch baking dish 5 minutes. Drain.
7. Spread 3/4 cup béchamel in bottom of a 13 x 9-inch baking dish coated with cooking spray. Arrange 3 noodles over béchamel; top with half of mushroom mixture, 1 1/2 cups béchamel, and 1/3 cup cheese mixture. Top with 3 noodles, spinach mixture, 1 1/2 cups béchamel, and 1/3 cup cheese mixture. Top with 3 noodles, remaining mushroom mixture, 1 1/2 cups béchamel, and 3 noodles. Spread remaining béchamel over noodles. Bake at 450° for 20 minutes. Sprinkle with remaining cheese; bake an additional 10 minutes. Let stand 10 minutes before serving.