Chicken Cordon Bleu Casserole

Preheat oven to 375 degrees F. Put a large pot of water on to boil. Cook broccoli in the boiling water until just tender and bright green, about 3 minutes. Transfer to a large bowl with a slotted spoon. Add pasta to the boiling water and cook according to package directions. Drain and rinse with cold water. Transfer to the bowl with the broccoli.

Heat butter in a large skillet over medium heat. Add chicken, onion, salt and pepper. Cook, stirring frequently, until the onion has softened and the chicken is no longer pink throughout, 6 to 8 minutes. Add flour and mustard. Stir until coated. Add milk and bring to a boil. Cook, stirring, until thickened slightly, 2 to 4 minutes. Transfer to the bowl with the broccoli and pasta. Stir in cheese, ham and parsley. Transfer the mixture to a 9-by-13-inch baking dish, spreading evenly. Combine panko and oil in a small bowl. Sprinkle over the casserole.

Bake until the casserole is heated throughout and the breadcrumbs are beginning to brown, about 30 minutes (or 50 minutes, if casserole has been frozen).