Easy Creamy Chicken and Spinach Casserole Recipe

Ingredients

• 3 tablespoons unsalted butter
• 1½ cups yellow onion, finely chopped
• 6 cloves garlic, thinly sliced
• 3 tablespoons all-purpose flour
• 2½ cups whole milk
• 4 cups shredded rotisserie chicken
• 3 cups cooked long-grain white rice
• 2 (10 ounce) packages frozen chopped spinach, thawed and drained
• 4 ounces chive and onion cream cheese
• 2 teaspoons dried Italian seasoning
• ¼ teaspoon crushed red pepper
• 1¾ teaspoons kosher salt, divided
• 2 tablespoons fresh lemon juice
• 1 teaspoon lemon zest
• 8 ounces part-skim mozzarella cheese, shredded
• ¼ cup Parmesan cheese, grated
• Cooking spray