Ingredients

BECHAMEL:

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

BECHAMEL:

  1. Place flour in a Dutch oven, and gradually add milk, stirring with a whisk.
  2. Add 1/2 cup onion, sage, shallots, 1/2 teaspoon salt, and bay leaf.
  3. Bring the mixture to a boil; cook 1 minute or until thick.
  4. Strain béchamel through a sieve over a bowl, and discard solids. Set the béchamel aside.

FILLING:

  1. 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.
  2. Add 1/2 teaspoon salt and spinach; sauté 2 minutes or until spinach wilts. Set aside.
  3. 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.
  4. Combine cheeses; set aside.

NOODLES:

  1. Soak noodles in warm water in a 13 x 9-inch baking dish 5 minutes. Drain.

ASSEMBLY:

  1. Spread 3/4 cup béchamel in bottom of a 13 x 9-inch baking dish coated with cooking spray.
  2. Arrange 3 noodles over béchamel; top with half of mushroom mixture, 1 1/2 cups béchamel, and 1/3 cup cheese mixture. Repeat and top with 3 noodles. Spread remaining béchamel over noodles.
  3. Bake at 450° for 20 minutes.
  4. Sprinkle with remaining cheese; bake an additional 10 minutes. Let stand 10 minutes before serving.