1/2 cup butter
1 onion, chopped
3 cloves garlic, minced
1/2 cup all-purpose flour
1 teaspoon salt
2 cups chicken broth
1 1/2 cups milk
4 cups shredded mozzarella cheese, divided
1 cup grated parmesan cheese, divided
1 teaspoon dried basil
1 teaspoon dried oregano
1/2 teaspoon ground black pepper
9 lasagna noodles
2 cups ricotta cheese
2 cups cubed cooked chicken meat
1 (10 ounce) packages frozen chopped spinach thawed and drained
1 8 oz package fresh sliced mushrooms