Creamy Ham & Potato Casserole

I know this one is from a magazine (I have the page I ripped out). But the bottom is missing... I'm guessing it's from Sunset which is the only one I subscribe to, but I'm not positive. Wherever it's from, it's good. :)

Creamy Ham & Potato Casserole
1 onion, chopped
2 Tbls butter
2 Tbls flour
2 Tbls Dijon-style mustard
1 3/4 cups milk
4 oz cream cheese, cut up
1 C Gruyere cheese, shredded (4 oz.)
1 Tbsp. fresh chives or green onions
1 1/2 lb. potatoes, cut in thin wedges
8 oz. cooked ham, coarsely chopped
1/2 cup coarsely crushed bagel chips
Thyme and/or Italian parsley leaves

1. Preheat oven to 350°. Grease a 2-quart rectangular baking dish; set aside.
2. For sauce, in medium saucepan cook onion in hot butter over medium heat 5 minutes or until tender; stirring occasionally. Stir in flour and mustard. Add milk. Cook and stir over medium heat until slightly thickened and bubbly. Reduce heat to low. Whisk in cream cheese until smooth. Gradually add 1/2 cup of the Gruyere cheese until cheese is melted. Stir in chives.
3. In bowl combine potatoes, ham, and sauce; toss gently to combine. Transfer to prepared baking dish.
4. Bake, covered, 1 hour or until potatoes are tender. Uncover; stir carefully. Sprinkle with crushed chips and remaining cheese. Bake, uncovered, 10 to 15 minutes more or until cheese is melted. Let stand, 10 minutes before serving. Sprinkle with herbs. Serves 6.

I used store-bought seasoned croutons instead of bagel chips. Taste fine, but they won't stay crispy as long...like for leftovers. :)