1/4 cup butter
1 cup chopped onion
4 cloves garlic, minced
1/4 cup all-purpose flour
1 cup milk
2 (14.5-ounce) cans diced tomatoes with basil, garlic, and oregano
1 (15-ounce) can tomato sauce
3 cups chopped cooked chicken
4 cups shredded mozzarella cheese, divided
1 1/2 teaspoons salt
1 teaspoon ground black pepper
1/2 teaspoon sugar
1 (16-ounce) package bow tie pasta, cooked according to package directions and kept warm
1. Preheat oven to 350°. Spray a 13x9-inch baking dish with nonstick cooking spray.
2. In a very large skillet, melt butter over medium-high heat. Add onion and garlic; cook, stirring occasionally, for 5 to 6 minutes or until onion is tender. Add flour, and cook, stirring constantly, for 2 minutes. Stir in milk, diced tomatoes, and tomato sauce; cook for 5 to 6 minutes or until slightly thickened. Stir in chicken, 3 cups cheese, salt, pepper, and sugar. Stir in pasta. Spoon mixture into prepared baking dish; sprinkle with remaining 1 cup cheese.
3. Bake for 25 to 30 minutes or until hot and bubbly.