Lasagne al Forno

To prepare mushroom sauce: Heat 1 1/2 teaspoons oil in a Dutch oven over medium heat. Add onion, carrot and celery; cook, stirring, until the onion has softened, about 5 minutes. Add mushrooms and garlic; cook until the mushrooms release their liquid, 2 to 3 minutes. Add wine; cook until most of the liquid has evaporated, about 5 minutes.

Stir in diced tomatoes, sun-dried tomatoes and thyme; bring to a simmer. Reduce heat to low and simmer, stirring often, until the sauce is thick, about 1 hour. Season with salt and pepper.

To prepare white sauce: Heat the remaining 1 tablespoon oil in a heavy saucepan over low heat. Add flour and cook, whisking constantly, until the flour starts to turn light brown, about 3 minutes. Remove from the heat and gradually whisk in milk. Return the pan to medium heat and cook, whisking constantly, until the sauce bubbles and thickens. Season with nutmeg and salt to taste.

To assemble & bake lasagna: Preheat oven to 375 degrees F. Coat an 8-by-11 1/2-inch baking dish with cooking spray.

Spread 1/2 cup of the mushroom sauce in the prepared pan, arrange a layer of noodles on top and spread with another 1/2 cup of the mushroom sauce. Arrange a layer of spinach over the sauce and drizzle with 1/3 cup of the white sauce. Sprinkle 2 tablespoons Parmesan over the spinach and top with another layer of noodles. Repeat this layering five more times. Spread the remaining white sauce over the top layer of noodles, covering completely. Cover with foil.

Bake the lasagna for 30 minutes. Uncover, sprinkle with the remaining Parmesan, and bake until golden, about 20 minutes longer. Let rest for 10 minutes before serving.