white cheese chicken lasagna... 1 hour and 20 minutes

the goods:

9 lasagna noodles (not oven-ready)
1/2 cup (1 stick) butter
1 yellow onion, chopped
1 garlic clove, minced
1/2 cup all-purpose flour
1 teaspoon salt
2 cups chicken broth
1 teaspoon salt
1 and 1/2 cups whole milk
4 packages (8 ounces each) sliced mozzarella
1 cup grated parmesan cheese, divided, plus an additional 1/4 cup for topping
1 teaspoon dried basil
1 teaspoon italian seasoning
1/2 teaspoon ground pepper
15 ounces whole milk ricotta cheese
2 cups cooked, cubed chicken (I sliced mine off of a rotisserie chicken)
1 package (10 ounces) frozen chopped spinach, thawed and drained
1 tablespoon fresh chopped flat-leaf parsley

Preheat oven to 350 degrees. Bring a large pot of salted water to a boil. Cook lasagna noodles in boiling water for 8-10 minutes. Drain and rinse with cold water, then lay flat on wax paper or foil to prevent sticking.
Meanwhile, melt the butter in a large saucepan over medium heat. Cook the onion and garlic in the butter until tender, stirring frequently, about 5-7 minutes. Stir in flour and salt, and cook until bubbly. Slowly stir in broth and milk, and bring to a boil, stirring constantly, for 1 minute. Stir in 3 slices of the mozzarella cheese, and 1/2 cup parmesan. Season with basil, italian seasoning, and black pepper. Remove from heat, and set aside. In a medium bowl stir together the ricotta and spinach until combined, set aside.
Spread 1/3 of the sauce mixture on the bottom of a 9x13-inch baking dish. Layer with 1/3 of the noodles, spread a layer of the ricotta/spinach mixture on top of the noodles, sprinkle with 1/2 of the chicken, drizzle with sauce, and layer with mozzarella slices, then sprinkle 1/4 cup parmesan on top. Add another layer of noodles, smear with remaining ricotta/spinach mixture, sprinkle with remaining chicken, drizzle with sauce, and layer mozzarella slices on top, the sprinkle with 1/4 cup parmesan on top. For the final later, lay out noodles, drizzle with sauce, and layer mozzarella slices on top. Sprinkle with 1/4 cup parmesan cheese.
Bake for 35 to 40 minutes. Let stand 5 minutes before cutting and serving.