Chicken Cheese Lasagna

1 medium onion, chopped
1 garlic clove, minced
1/2 cup butter
1/2 cup all purpose flour
1 teaspoon salt
2 cups chicken broth
1 1/2 cups milk
4 cups (16 ounces) shredded part skim mozzarella cheese, divided
1 cup grated Parmesan cheese, divided
1 teaspoon dried basil
1 teaspoon dried oregano
1/2 teaspoon white pepper
2 cups (15 to 16 ounces) ricotta cheese
1 tablespoon minced fresh parsley
9 lasagna noodles, cooked and drained
2 packages (10 ounces each) frozen spinach, thawed and well drained
2 cups cubed cooked chicken

In a large saucepan, saute onion and garlic in butter until tender. Stir in flour and salt until blended; cook until bubbly. Gradually stir in broth and milk. Bring to a boil; cook and stir for 1 minute or until thickened. Stir in 2 cups mozzarella, 1/2 cup Parmesan cheese, basil, oregano and pepper; set aside.
In a large bowl, combine the ricotta cheese, parsley and remaining mozzarella; set aside. Spread one-quarter of the cheese sauce into a greased 13 inch x 9 inch baking dish; cover with one-third of the noodles. Top with half of the ricotta mixture, half of the spinach and half of chicken.
Cover with one-quarter of the cheese sauce and one-third of noodles. Repeat layers of ricotta mixture, spinach, chicken and one-quarter cheese sauce. Cover with remaining noodles and cheese sauce.
Sprinkle remaining Parmesan cheese over all. Bake at 350 degrees, uncovered, for 35-40 minutes. Let casserole stand 15 minutes.